CALIFORNIA AGRICULTURAL EXTENSION SERVICE CIRCULAR 108 August, 1938 FEEDING CHICKENS H. J. ALMQUIST, T. H. JUKES, and W. E. NEWLON Cooperative Extension work in Agriculture and Home Economics, College of Agriculture, University of California, and United States Department of Agriculture cooperating. Distributed in furtherance of the Acts of Congress of May 8, and June 30, 1914. B. H. Crocheron, Director, California Agricultural Extension Service. THE COLLEGE OF AGRICULTURE UNIVERSITY OF CALIFORNIA BERKELEY, CALIFORNIA CONTENTS PAGE Nutrients 3 Proteins 3 Carbohydrates 4 Fats 5 Vitamins 5 Vitamin A 6 Vitamin Bi (thiamin) 7 Vitamin C (ascorbic acid) 7 Vitamin D 7 Vitamin E 8 Vitamin-G complex 8 Vitamin K 9 The gizzard factor 9 Other vitamins 10 Minerals 10 Feedstuffs as mixtures of essential nutrients 11 Composition 11 Digestibility 11 Bulk _ 13 Wet vs. dry feeding 13 Individual characteristics of feedstuffs 13 Energy concentrates 13 Barley 13 Sorghum grains 14 Corn 14 Oats 14 Wheat 14 Wheat by-products 14 Rice 14 Rice by-products 15 Cane molasses 15 Potatoes 15 Field peas, cowpeas, and beans 15 Digestible energy values of the common grains 15 Protein concentrates 17 Fish meal 17 Meat scraps and tankage 17 Milk products 17 Oil-cake meals 18 Animal vs. vegetable protein concentrates 19 Mineral supplements 19 Salt 19 Phosphorus 19 Calcium 20 Computation of calcium and phosphorus levels 22 Manganese 23 Other minerals 23 Charcoal 24 Grit 24 Water 24 Vitamin supplements 24 Feeds sypplying vitamin A 24 Feeds supplying vitamin D 26 Feeds supplying vitamin-G complex 27 Feed formulas 30 Feeding laying hens 30 Feeding growing birds 33 Feeding breeding hens 34 Feeding molting birds 35 Feeding table poultry 36 Weight standards 38 FEEDING CHICKENS 1 H. J. ALMQUIST 2 , T. H. JUKES 3 , and W. E. NEWLON 4 Domestic birds, like all other animals, utilize food for two main pur- poses : (1) as building material for the construction of new tissues and their products; (2) as a source of energy. At all times newly formed tissue is needed for replacement of the tissue destroyed by the general wear and tear of the body. The body also needs energy for maintaining its temperature and for all the bodily activities. Food is composed of several distinctly different groups of substances, which are called "nutrients." Of these the following groups are recog- nized : proteins, carbohydrates, fats, vitamins, and minerals and water. NUTRIENTS PROTEINS Protein is the name of a group of very complex organic substances which always contain carbon, hydrogen, oxygen, and nitrogen. In addition, proteins usually contain sulfur and frequently phosphorus. These sub- stances are widely distributed in plants, which build them up from simple sources in the soil and air. Proteins are the main constituent of animal tissues, which must derive them directly or indirectly from plant tissues. Birds require protein in their rations for the formation of new body protein, such as flesh and feathers; for the production of eggs; and for the repair of worn-out tissues. A bird's body contains as much protein as all other groups of nutrients together, if water is excepted. Twenty per cent of the live weight and practically 50 per cent of the dry weight is protein. The importance of this group of nutrients in feeding is there- fore easy to understand. The proteins are extremely complex and are composed of many simpler units called the "amino acids" of which about 22 are known. The amino acids are sometimes spoken of as "building stones," because just as stones are used to build, so does the body of the bird use amino acids to build proteins of various types. During digestion, the proteins in the food are 1 This circular supersedes Bulletin 417, Poultry Feeding : Principles and Practice, by Walther P. Hoist and Wilson E. Newlon. Certain parts of Bulletin 417 have been quoted in full or in part with permission of the junior author. 2 Assistant Professor of Poultry Husbandry and Assistant Poultry Husbandman in the Experiment Station. 3 Instructor in Poultry Husbandry and Junior Poultry Husbandman in the Experi- ment Station. 4 Specialist in Agricultural Extension. [3] 4 California Agricultural Extension Service t ClR - 108 broken down into amino acids, which pass into the blood stream and travel to various parts of the body where they may be used for building up new proteins. Certain of the amino acids can be formed in the bird's body from other substances if the supply in the food is insufficient, while others cannot. Hence these latter are called essential amino acids because it is essential to provide them in the diet. This is done by feeding a mixture of proteins which, when added together, supply enough of the essential amino acids. Some proteins may lack an essential amino acid but contain certain others. Such proteins are sometimes called "incomplete" proteins. No protein lacks all the essential amino acids, and the incomplete proteins are valuable in feeding, especially when they compensate each other by being fed as a mixture of proteins. Any amino acids that are left over after the requirements have been completed are destroyed in the liver. In this destruction a part of each amino acid is turned into fuel, and the remainder is excreted by the kid- neys. Hence, proteins in the ration can serve not only as building mate- rial but also as a source of energy. Proteins are expensive, however, and carbohydrates are more economical to use as a source of energy. Proteins cannot be absorbed into the body in the form in which they are fed. They must be digested and broken down into amino acids, which are then taken into the blood stream. Some proteins fail to dissolve in the digestive juices, and hence are valueless as poultry food. Since pro- teins vary both in their digestibility and in the amino acids which they contain, feeding experiments are necessary to determine the value of various proteins in poultry rations. An ordinary chemical analysis of a feed tells how much protein it contains but does not give any information concerning the value of the protein for use in the body. CARBOHYDRATES These compounds contain only three chemical elements : carbon, hydro- gen, and oxygen. The carbohydrate group includes such substances as sugars, starch, gums, and celluloses. The celluloses, however, are gener- ally classed separately under "crude fiber," in tables giving the composi- tion of feeds. Crude fiber is largely indigestible for poultry. Starch is by far the most common carbohydrate in poultry rations. It occurs in large amounts in cereal grains and is the principal source of energy in poultry nutrition. In the course of digestion, the carbohydrates are broken down into the simplest kind of sugars, in which form they are absorbed. Carbohydrates in the animal body are stored only temporarily as carbohydrates and are Feeding Chickens 5 either used comparatively soon, or stored as fat, into which they are readily convertible. FATS Fats are compounds of glycerin and the fatty acids (commonly stearic, palmitic, and oleic acid). Like carbohydrates, they contain the three elements, carbon, hydrogen, and oxygen. In the digestive tract, fats from the food are broken down (digested) to free the fatty acids and glycerin, which pass through the intestinal wall, immediately to be recombined into fats. If not needed immediately as a source of energy, they are deposited within the cells and in the adi- pose, or fatty, tissue. In the feeding of poultry and other domestic animals, carbohydrates, rather than fats, are fed as the principal source of energy. This is be- cause carbohydrates are cheaper and are very easily digested, absorbed, and utilized or transformed into fat. Fats, on the other hand, are digested only with difficulty, and are absorbed slowly. These difficulties are such that large proportions of fat in the food may retard digestion and upset the normal metabolism of the other nutrients. Consequently, large amounts of fat are always to be avoided in animal feeding. Feeds which contain large amounts of fat are apt to become rancid in hot weather, and rancid feed is injurious to poultry. Fats are much more expensive than carbohydrates, and hence do not find their way in quan- tity into ordinary rations. Small amounts of fat, however, are necessary as carriers of the fat-soluble vitamins. Such small amounts are present in nearly all natural foodstuffs. Other substances of a fatlike nature are present in feeds. The term "crude fat" includes these substances as well as the true fats. Some of these fatlike substances may be partly broken down into fats and used for energy, but others do not have any known food value. VITAMINS Small amounts of these substances must be fed in order to keep the body in good working order. Several of the vitamins are well known, and some have been made artificially. Recent investigations indicate that other vitamins have yet to be discovered. If a ration low in vitamins is fed for a sufficient length of time, the result is inevitably disease (so-called "deficiency disease") and eventually death. Unlike the other classes of nutrients, which are comparatively stable chemical compounds, many of the vitamins are more or less unstable, which makes their study much more difficult. Because of this instability, care must always be taken to insure an ample supply of vitamins in 6 California Agricultural Extension Service t ClR - 108 poultry rations. When the individual needs have been covered, an excess can in certain cases be stored in the animal tissues and in the egg. Vitamin A. — Animals fed on an otherwise perfect ration, but lacking vitamin A, stop growing, and may develop a form of paralysis. Beach and Freeborn 6 state : [The symptoms of vitamin-A deficiency] are decrease in appetite, weakness and emaciation, droopiness, reddened and watery eyes which may be followed by the formation of an adherent white film over the third eyelid and a mass of white cheesy material within the eyelids ; the formation of yellowish white, round cheesy pustule- like patches in the mouth and throat, of about the size of a pinhead ; and occasionally the formation of masses of white cheesy material in the cleft or elsewhere in the mouth. . . . Post-mortem examination of birds that have died usually shows the kidneys to be very pale and marked with a network of very fine white lines. Occasionally a deposit of white material is also found on the surface of the liver, on the membrane around the heart, or elsewhere on the surface of the organs. This condition in birds is also called "nutritional roup." It can be pre- vented or cured by feeding substances known to be good sources of vita- min A. Naturally an adult hen deficient in vitamin A will not lay well, and her eggs will not hatch well. Plants synthesize a yellow pigment called "carotene." It is present in green parts of all plants, and in certain yellow parts of some, such as yellow corn and carrots. Birds change carotene to vitamin A in their livers. Hence they may get their supply of vitamin A from the carotene of plants, or from fish oils, in which vitamin A has already been formed by fish from the carotene present in sea plants. Birds can utilize either the animal form of vitamin A or the plant form (carotene) equally well. Hens store vitamin A in their livers and egg yolks. The amount stored in the egg yolk depends on the amounts of carotene and vitamin A fed to the hen. The yellow color of egg yolks, however, is due to another plant pigment called "xanthophyll" which cannot be used as a source of vita- min A. When vitamin A and carotene are exposed to the air, particularly at warm temperatures, they are gradually destroyed. For example, when fish oil is mixed in a mash, it becomes exposed to the air at the surface of the feed particles, and the vitamin A in the oil tends to diminish. Caro- tene in plants, such as alfalfa, is fairly well preserved when the curing conditions are favorable ; that is, when the drying is accomplished rap- idly, but without exposure to excessively high temperatures or prolonged exposure to sunlight. A loss occurs on storage; three-quarters of the 5 Beach, J. E., and S. B. Freeborn. Diseases and parasites of poultry in California. California Agr. Ext. Cir. 8(5th ed.) : 49. Revised 1936. Feeding Chickens 7 original vitamin-A potency in baled alfalfa hay has been reported lost during a year's storage. Vitamin B x (Thiamin). — Vitamin B lt also called the "antineuritic vitamin," is found in the germ and bran of all grains, and to a smaller ex- tent in other f eedstuffs. Hence, it is plentifully present in every ordinary poultry ration and does not need to be fed in extra quantities by provid- ing special supplements. It is very stable ; exposure to air and even mod- erate dry heat does not destroy it. A deficiency of this vitamin in the diet causes a nervous disorder in poultry, called "avian polyneuritis." This disease is not known to occur in birds given practical rations, since whole grains and grain by-products, as used in an average poultry ration, sup- ply more than twice the level of vitamin B 1 required by chickens. Vitamin C (Ascorbic Acid). — This vitamin is not needed in poultry diets. Apparently birds are able to make this substance in their own bodies. Vitamin D. — This vitamin, known as the "antirachitic factor," is per- haps the most peculiar of the vitamins, since its place may be taken by certain light rays. These rays are usually referred to as the ultraviolet rays or ultraviolet light. They are rays of comparatively short wave length found in sunlight and may be produced artificially by mercury vapor or carbon arc lamps. These rays change certain substances in the skin to vitamin D. Vitamin D is contained in a few animal fats where it often, but not always, occurs associated with vitamin A. Outstanding sources of vita- min D are various fish oils, such as cod-liver oil, sardine oil, etc. Vitamin D is now known to exist in several forms. One of them is very effective for poultry, and is found in sardine oil and in cod-liver oil. An- other form very effective for rats, but not relatively so effective for poul- try, is present in certain artificial preparations of the vitamin, such as irradiated yeast, which are used principally for human feeding. Still another form, found in certain fish oils, is relatively more effective for chicks than for rats. In growing chicks a lack of vitamin D results in a bone disease called "rickets," which is characterized by lameness, swelling of the joints, and bone deformities. The symptoms are due to the fact that calcium and phosphorus are not being adequately deposited in the bones. Even with an abundance of calcium and phosphorus in the diet, the birds cannot make use of them unless vitamin D is provided either in the ration or by exposure to ultraviolet light. Adult birds may suffer from a disease similar to rickets. Laying hens will produce eggs for a certain period regardless of whether vitamin D 8 California Agricultural Extension Service [Cir. 108 is supplied or not. If this factor is lacking, the calcium in the diet cannot be made use of, and the hen will deprive her own bones of calcium in order to form normal eggs. She may in this way ultimately develop a severe case of calcium-deficiency disease. The crooked breastbones ob- served in good layers are often a result of the lack of vitamin D and the depletion of the calcium supply in the bones. Vitamin E. — For normal functioning of the reproductive organs of animals, vitamin E is necessary. Laying hens and breeding males have Fig. 1. — A chick afflicted with curled-toe paral- ysis caused by an inadequate supply of riboflavin in the diet. Note the typical posture and the inwardly curled toes. been shown to require the vitamin for normal fertility and hatchability. However, this vitamin is contained in whole grains, fresh greens, and alfalfa meal to such an extent that the fowls' needs seem to be completely supplied by ordinary rations. Vitamin-G Complex. — What was formerly known as vitamin G, has recently been shown to consist of several factors. The most important of these is a yellow pigment known as "riboflavin," "flavin," or "lacto- flavin" ; in fact, in poultry feeding, the term "vitamin G" frequently re- fers primarily to riboflavin, which is of great importance in growth and hatchability. Chickens have a high requirement for riboflavin. Some of the symptoms of riboflavin deficiency in chicks are curled-toe paralysis (fig. 1), slow growth, and inefficient utilization of food. The primary source of this vitamin is green leaves, fresh or dried. Milk and whey are also good sources of riboflavin. The beneficial effect of alfalfa meal, fresh greens, milk, and whey in poultry rations is principally due to the ribo- flavin which these feeds supply. While 2 parts of fresh greens per 100 parts of total ration supply the complete vitamin-A requirement of a Feeding Chickens 9 chick, about 50 parts of fresh greens would be necessary to satisfy the riboflavin requirement. Consequently, more than one source of riboflavin is customarily included in the ration. Riboflavin is a vitamin that every- one may see, for it gives the greenish-yellow tinge to raw egg white. The second factor of the vitamin-G complex which has been shown to be needed by chicks is the "filtrate factor," or "antidermatitis vitamin." Deficiency of this factor in the diet of chicks results in slow growth, a frequently bloody incrustation at the corners of the mouth, and a thick- ening of the eyelids, which tend to become stuck shut (fig. 2). The feathers Fig. 2. — A chick suffering from dermatitis caused by a lack of the filtrate factor (antidermatitis vitamin) in the diet. Note the incrustation at the corners of the mouth and the tightly stuck eyelids. break off at the base and give the chick a ragged appearance. The filtrate factor has a different distribution from riboflavin. For example, fresh greens, which are a good source of riboflavin, contain practically no fil- trate factor, while cane molasses, which is a good source of the filtrate factor, is very low in riboflavin. Experiments indicate that the filtrate factor is not of great practical importance in egg production and hatchability. However, rich sources of this vitamin should be provided in breeding diets in order that the chick may have a good reserve store at hatching. Vitamin K. — Fowls require vitamin K, also known as the "antihemor- rhagic vitamin," for normal blood-clotting power and for the prevention of excessive bleeding from small wounds or from other forms of hemor- rhage. It is abundantly supplied by fresh or dried greens. A deficiency of this vitamin in practical diets is very unlikely. The Gizzard Factor. — Gizzard erosions (also referred to erroneously as ulcers) have been reported both in laboratory investigations and in pathological studies of commercial poultry. These erosions consist of 10 California Agricultural Extension Service L Cir - 108 areas in which the yellow gizzard lining appears to be rough, frayed, or entirely absent. The eroded areas may be brown or black. They occur on almost any portion of the lining but most often at the cardiac, or forward, end. Occasionally the tissues beneath the eroded area are also affected. Recent studies have indicated that this gizzard disease is the result of a dietary deficiency. The preventive factor is found in fresh and dried greens, wheat bran, rice bran, hempseed meal, and soybean meal. A ration containing 5 per cent of a good grade of dried alfalfa and 15 per cent of wheat bran has prevented the gizzard erosions, except in a few instances in very young chicks. Kale appears to be a somewhat better source of the gizzard factor than alfalfa. Other sources remain to be found. Granite grit has been found to have a diminishing effect on gizzard erosions, pre- sumably by increasing the activity of and the blood supply to the gizzard. The erosions are not a symptom of a fungus infection sometimes found in the crop or gizzard and commonly called "mycosis." Severe gizzard erosions have been experimentally produced in chicks which were com- pletely free from mycosis. A few field cases have been noted in Avhich both mycosis and erosions were present, but the two conditions are basically of widely different origin. The erosions tend to disappear as the chicks become older, probably because of a lowering of the requirement for the gizzard factor. Gizzard erosion or a deficiency of the gizzard factor does not appear to affect growth, since birds with severe erosions raised on otherwise adequate diets to 4 and 6 weeks of age have attained practically the same body weights as those birds in which gizzard erosions were pre- vented or cured by supplementing the diet with a potent source of the gizzard factor. There is evidence, however, that other conditions or defi- ciencies which retard growth and development may indirectly increase the severity of gizzard erosions. Other Vitamins. — Chicks do not thrive when they are placed on an artificially purified diet which contains all of the known vitamins. This indicates that other nutritional factors exist. For example, two different new factors are known which are required to prevent certain forms of nutritional paralysis. These factors are obviously present in ordinary practical rations. MINERALS Growing birds need a constant supply of minerals so that they may be enabled to form new bone and other tissues which contain minerals. Lay- ing birds must also be provided with the essential minerals for eggshell formation. All birds should be constantly supplied with minerals, be- cause minerals are continually being excreted. Large quantities of calcium and phosphorus are needed for bone for- Feeding Chickens 11 mation and calcium for shell formation, also. Calcium, phosphorus, sodium, chlorine, potassium, magnesium, and possibly small traces of other minerals must be present in all the body fluids for normal func- tioning of the body. Iodine is required in small quantities for normal activity of the thyroid gland. Iron is present in eggs and is also an im- portant constituent of the hemoglobin, the chief oxygen carrier of the blood. Besides these, zinc and manganese are found in small quantities, although the requirements are very small. Small amounts of manganese must be present in the ration to prevent a bone deformity known as "slipped tendon" in growing birds. FEEDSTUFFS AS MIXTURES OF ESSENTIAL NUTRIENTS COMPOSITION In the preceding sections, the nutrients have been considered as well- defined groups of substances. This was to explain clearly their individual characteristics and behavior. In practical feeding, however, it is not the separate nutrients which are dealt with, but feedstuffs, which are mix- tures of nutrients. The fact that the nutrients are present as a mixture does not affect the underlying principles of nutrition. The proportions in which they are present can be estimated by analysis. Tables of the composition of feedstuffs give the average percentage of these classes of nutrients, as in table 1, page 12. DIGESTIBILITY Although analyses of feeds are of great importance, of still greater importance to the practical feeder is the digestibility of the feed. Such information can be obtained only by actual feeding tests under carefully controlled laboratory conditions. Since different kinds of animals have marked differences in their di- gestive systems, the digestibility will vary for different species and has to be determined for each species (that is, separately for cattle, horses, hogs, chickens, etc.). Because of the experimental difficulties caused by the combined excretions of feces and urine, work with chickens has been conducted on a limited scale only. Digestibility coefficients obtained in experiments with other kinds of animals, even with other species of poultry, may be very misleading when applied to chickens. Certain feed- stuffs possess unique values in poultry nutrition which completely over- shadow digestibility considerations. Moreover, the digestibility of any one kind of feedstuff as determined by feeding it alone to experimental birds may be different from its digestibility when fed as one component of a complete mixed feed. 12 California Agricultural Extension Service [Cir. 108 TABLE 1 Approximate Percentage Composition of Feedstuffs Used for Poultry Feedstuff Crude protein Nitrogen- free extract* Crude fat Crude fiber Calcium Phosphorus Alfalfa meal, whole Alfalfa leaf meal Alfalfa, fresh 17.6 21.1 4.7 22.4 8.7 7.1 12.5 20.0 11.9 21.0 9.6 11.1 19.8 26.4 23.8 43.2 23.8 12.7 22.9 70.0 68.0 62.0 56.0 9.7 31.1 10.6 0.0 37.0 65.4 55.0 50.8 33.8 11.3 34.8 12.5 12.1 11.1 4.7 9.6 16.4 0.0 43.4 2.1 8.3 7.4 12.8 12.7 12.3 43.0 44.3 16.1 12.3 9.9 15.8 28.1 17.4 16.8 17.9 38.7 39.8 11.0 44.2 71.0 3.9 3.1 43.6 63.8 45.0 68.4 70.8 53.2 48.4 52.3 27.0 57.1 69.1 57.8 3.0 3.5 3.0 3.0 73.7 23.3 69.9 0.0 37.0 4.5 1.2 2.0 41.9 13.3 50.1 72.1 61.0 71.4 61.9 62.2 66.0 0.0 25.0 16.3 64.5 78.4 41.1 57.2 71.7 24.0 30.3 21.3 71.1 72.6 54.3 44.7 56.1 56.9 57.8 3.0 2.8 0.8 6.4 1.9 3.3 6.5 5.7 2.4 7.0 3.8 5.1 7.8 2.5 1.8 7.2 1.4 2.8 1.1 8.0 8.5 8.0 10.0 2.5 6.6 2.7 0.0 2.9 16.5 10.7 11.1 5.6 1.6 0.9 0.7 4.1 2.9 0.0 7.2 5.9 0.0 8.2 0.1 1.8 0.6 13.4 11.6 1.7 7.0 5.7 24.7 1.8 2.0 5.0 9.5 5.5 4.9 4.5 26.0 16.1 8.0 11.8 5.7 0.8 0.6 18.1 10.3 9.0 2.3 1.9 8.9 7.1 11.3 10.7 4.3 2.4 5.6 1.5 1.0 0.9 1.7 2.3 22.8 2.3 0.0 8.7 0.8 2.2 2.1 0.4 0.1 0.3 0.1 8.4 2.5 0.0 8.7 1.9 0.0 10.0 0.6 8.9 0.8 13.0 3.2 2.3 6.0 5.6 27.9 2.4 2.7 9.5 2.6 6.8 7.2 5.6 1.43 1.90 0.36 0.30 0.05 32.60 26.00 0.25 0.04 0.21 0.01 0.02 0.04 0.14 0.05 0.24 0.12 0.02 0.07 4.49 4.90 5.20 6.70 0.03 0.47 0.04 38.90 0.33 0.13 8.70 10.90 1.40 0.50 1.20 1.20 0.01 0.01 0.60 0.08 0.09 38.00 0.18 1 0.07 0.04 0.08 0.04 0.04 2.02 0.28 0.11 0.03 0.03 0.12 0.06 0.08 0.11 0.09 0.21 0.22 0.05 0.67 Barley 0.38 Bone meal, steamed Bone meal 15.20 12.70 Brewers' grains, dried Buckwheat 0.47 0.29 0.62 Corn, yellow dent Corn, Argentine flint Corn germ meal Corn gluten feed Corn oil meal 0.28 0.31 0.58 0.55 0.57 Cottonseed meal . . 1.11 Cowpeas 0.42 Feterita 0.32 Field peas 0.40 Fish meal Herring Whole sardine Sardine scrap Tuna scrap 3.08 2.90 3.00 3.70 Hegari 0.31 Hempseed meal 0.55 0.30 0.10 0.86 Liver meal Meat scrap, 55 per cent Meat scrap, 50 per cent Milk products Buttermilk, dried Buttermilk, condensed. . Skim milk, dried Whey, dried 0.75 4.30 5.20 0.80 0.30 1.00 0.70 Millet Milo 0.32 0.34 Molasses, cane 0.10 0.30 Oats, hulled 0.44 Oystershell 0.60 Peanut meal 0.57 Potatoes 1 0.21 Rice, brewers' 0.10 1.36 1.10 Rye 0.37 1.61 0.66 0.55 Wheat, hard Wheat, Pacific Coast 0.43 0.42 1.32 Wheat germ meal Wheat middlings, standard . 0.97 0.92 1.09 Wheat gray shorts 0.86 * Total extractable crude carbohydrates, t Dashes indicate data not available. Feeding Chickens 13 The chicken is a fast-growing and high-producing animal requiring a concentrated diet which can be rapidly assimilated. Slowly digested feeds, of some nutritive value for certain other animals, may be of negli- gible value for chickens. Hence, the fact that a feedstuff may be used in feeding dairy cows does not prove that it is satisfactory for use in poultry feeding. BULK All poultry rations furnish more or less bulk, a large part of which is in the form of crude fiber. The amount of bulk required for best results remains an open question. There appears to be a rather large margin of safety within which variations do not seem to make a perceptible differ- ence. Thus, certain rations with as little as 2 per cent crude fiber and others with as much as 10 per cent have given good results. Most common rations, with 6 per cent crude fiber, have more than 6 per cent of bulk because of other indigestible matter. One ration comparatively low in fiber may furnish far more bulk than another containing more fiber. There is no evidence in support of the prevalent opinion that the presence of bulk is of assistance in "opening up" the rest of the food to digestion. WET VS. DRY FEEDING Many poultrymen make a practice of feeding part of the ration in the form of a damp mash in order to increase the palatability. However, there is no evidence to show that the birds will not consume sufficient dry feed. Wet-mash feeding involves extra work and presents the danger that feed may become spoiled by action of molds and bacteria, especially in hot weather. The same criticisms apply to "fermented" feeds. INDIVIDUAL CHARACTERISTICS OF FEEDSTUFFS The common f eedstuffs may be roughly classified as energy concentrates, protein concentrates, mineral supplements, and vitamin supplements. ENERGY CONCENTRATES This class of feedstuffs consists of the grains and their by-products and other feedstuffs which are predominantly composed of carbohydrates. Energy concentrates also supply some vitamins, especially B x and E ; minerals, especially potassium, phosphorus, magnesium, iron, and man- ganese ; and some protein. Barley. — In California a number of poultrymen have fed a ration con- taining as high as 75 per cent of barley with good results. In areas where barley is favorable in price, it may well be fed as the only scratch grain, and variety may be provided by using other grains and their by-products 14 California Agricultural Extension Service t ClR - 108 in the mash. Birds raised on other grains do not consume barley readily, but if trained to eat it early enough they like it and consume it as freely as any other grain. Whole barley may be fed to chicks at as early an age as 3 weeks. A fairly good indication of the feed value of different grades of barley is the weight per bushel. Obviously, the heavier the barley, the higher, as a rule, is the feed value. The light-grade barley, in order to deserve con- sideration, should be obtainable at correspondingly low prices. Light bar- ley screenings and hulls should under no consideration be used as feed for poultry. Sorghum Grains. — Milo, Egyptian (or "gyp") corn, kafir, and other sorghums are important grains for poultry feeding in California. These grains have a high digestible energy value and are very low in fiber. They are usually much cheaper than corn and similar to it in composition. Milo is "the corn of the West," and may well be used in western poultry rations as fully equivalent to yellow corn when price and availability warrant the change. Corn. — Yellow corn is a valuable grain for poultry, being highly palat- able, highly digestible, and often reasonable in price. Yellow corn differs from white corn and most other grains in that it provides vitamin A. The amount contained is, however, rather small, about 7 units of vitamin A per gram as compared with 100 units per gram for young fresh alfalfa. Yellow corn also contains the pigment which gives yellow color to the skin and shanks of the bird and to the egg yolk. Argentine flint corn has the same feeding value for poultry as domestic yellow corn, but has a greater tendency to darken the yolk color owing to its greater content of pigments. Oats. — Oats are a desirable feed for poultry, although even heavy oats have a comparatively low feed value because of the large proportion of hulls. Wheat . — Wheat is another popular feed for poultry. In feed value it ranks slightly below yellow corn, but above barley and oats. Wheat By-Products. — The most important of the wheat by-products are wheat bran, mill run, and wheat middlings. They are popular feeds for poultry. Wheat by-products are lower in digestible energy value than whole wheat and somewhat higher in fiber, vitamins, and minerals. Experiments at the California Agricultural Experiment Station have shown that wheat bran is a useful addition to the ration, and should be included, especially in chick rations. Rice. — Rice is produced in California in considerable amounts. While the superior grades are too expensive for use in poultry feeding, off-grade Feeding Chickens 15 paddy rice and screenings, like cracked rice and brewers' rice, can often be obtained at attractive prices. Rice is high in digestible energy value, but low in protein. Rice By-Products. — Such rice by-products as rice bran and rice polish are valuable and palatable feeds. Their fat content, however, is so high that they should not, individually or in combination, make up more than 10 per cent of the mash. Used inside of such a limit, they give very satis- factory results. Only well-dried brans of low moisture content should be fed to poultry. Rice bran is sometimes contaminated with rice hulls, screenings, and lime, which lower its feeding value for poultry. Cane Molasses. — Cane molasses is a feed commodity that has a distinct value as an energy concentrate. It should not be fed at a higher level than 5 per cent of the mash, because larger amounts are too laxative. Molasses also supplies the nitrate factor. It is difficult to mix in the ration, but the difficulty may be overcome by using dehydrated molasses; 4 pounds of dehydrated molasses is equivalent to 5 pounds of liquid mo- lasses. Molasses has the further advantages of cheapness and palatibility. 6 Potatoes. — Potatoes are sometimes fed in small quantities, but they should be cooked before feeding. Five pounds will be necessary to replace 1 pound of grains. Field Peas, Cowpeas, and Beans. — These may replace 5 to 10 per cent of the grain in a poultry ration when they are available at a low price. Digestible Energy Values of the Common Grains. — As a partial aid in the selection of the commoner whole grains in poultry feeding, con- sideration may be given to the digestible energy values (total digestible nutrients) of these grains as computed from recent digestibility results obtained with the chicken by improved methods. On the basis of such calculations, 100 pounds of yellow corn is found to contain digestible nutrients (protein, fat, and carbohydrates) equiv- alent in energy-producing value to 75.5 pounds of starch. "Wheat has a corresponding value of 72.1; barley, 66.1; oats, 63.6; and rye, 71.0. Wheat-bran calculations based on somewhat older data yield a figure of 45.2. Thus from the energy standpoint it may be computed that 105 pounds of wheat, 114 pounds of barley, 119 pounds of oats, and 107 pounds of rye are each equal to 100 pounds of corn. To express the com- parison in another way, wheat has 95.5 per cent of the digestible energy value of corn, barley has 87.5 per cent, oats 84.3 per cent, and rye 94.0 per cent. There is no evident reason why the use of the better grades of corn, 6 Information on mixing molasses in feeds is given in detail in: Fairbank, J. P., and J. R. Tavernetti. Handling feed molasses on the farm. Univ. California Col. Agr., Agr. Engin. Inform. Ser. No. 11:1-7. 1937. (Mimeo.) 16 California Agricultural Extension Service [ Cir . 108 wheat, barley, and oats in poultry feeding" should not be governed prin- cipally by such figures. Rye and wheat bran, however, are two outstand- ing exceptions to this method of rating f eedstuffs : the former being unsuitable in any considerable amounts in chick mashes because of a tendency to cause diarrhea and slow growth, and the latter possessing more general feeding value for poultry than considerations of digestible energy would indicate. It may be further pointed out that digestible energy values are not logically to be used in connection with protein concentrates such as fish TABLE 2 Comparative Equivalent Prices per 100 Pounds of Good Grades of Grains Based on the Digestible Energy Values of the Grains for Poultry Corn Wheat Barley Oats Corn Wheat Barley Oats $1.20 $1.15 $1.05 $1.01 $1.75 $1.67 $1.53 $1.47 1.25 1.19 1.08 1.05 1.80 1.72 1.57 1.51 1.30 1.24 1.14 1.09 1.85 1.77 1.62 1.57 1.35 1.29 1.18 1.14 1.90 1.81 1.66 1.60 1.40 1.34 1.22 1.18 1.95 1.86 1.71 1.64 1.45 1.38 1.27 1.22 2.00 1.91 1.75 1.68 1.50 1.43 1.31 1.26 2.05 1.96 1.79 1.72 1.55 1.48 1.37 1.30 2.10 2.00 1.84 1.77 1.60 1.53 1.40 1.35 2.15 2.05 1.88 1.81 1.65 1.57 1.44 1.39 2.20 2.10 1.92 1.85 $1.70 $1.62 $1.49 $1.43 $2.25 $2.15 $1.97 $1.89 meal and meat scrap, which are employed, practically, as sources of pro- tein rather than energy. Hence the calculation of total digestible nutri- ents in a complex mixture such as a mash for chickens is a meaningless procedure. Table 2 gives the prices per 100 pounds of grains that are in proportion to the digestible energy values of these grains for poultry. These prices have been calculated from the data above. For example, if corn is selling at $1.80 per 100 pounds the poultryman should not pay more than $1.72 for wheat, $1.57 for barley, and $1.51 for oats. As a further example, if barley can be obtained at $1.14 per 100 pounds, it represents a better value for the money than corn at $1.45 or wheat at $1.38. As previously mentioned, these figures apply to the better grades of grains. They obviously do not furnish a basis of choice between a good grade of one grain and a very poor grade of another. Feeding Chickens 17 PROTEIN CONCENTRATES Fish Meal. — Fish meal or fish scrap is one of the most valuable protein concentrates. Unless the fat content is far above the average, which is between 6 and 8 per cent, fish meal, even when fed in large amounts, does not give taste or odor to the eggs or meat of birds to which it is fed. Fish proteins are of high nutritional value and are therefore well suited for supplementing grain rations for poultry. Fish meals, as they are now being manufactured on the Pacific Coast, are practically all made from whole fish or cuts of fish. The cooking necessary for the removal of the oils is only of a few minutes' duration, and the drying is more and more being carried out at low temperatures under vacuum or by other methods which prevent oxidation. Fish meals contain certain desirable mineral elements such as calcium, phosphorus, iron, and iodine. Pacific Coast fish meals vary in protein content from 56 per cent to as high as 75 per cent. The method of manufacture of the fish meal is of far greater importance than its percentage of crude protein. Fish meal pre- pared by vacuum-drying or steam-drying will be more digestible than fish meal prepared by flame-drying, but the percentage of crude protein may be the same in both cases. Furthermore, fish meals prepared from such a source as whole sardines will be of much greater value than if pre- pared from fish waste. If prepared from anything but fresh materials, they should be used only for fertilizer. Fish meals dried with excessive heat do not deserve the same price as high-quality meals. Meat Scraps and Tankage. — These are packing-house products which resemble each other closely, the difference being that tankage is allowed to contain dried blood and "stick," while meat scraps must consist of dry rendered residues only, to which no blood and stick have been added. Stick is partially evaporated tank water containing water-soluble pro- tein-decomposition products, gelatin, and other nitrogenous materials of low nutritive value. Both meat scraps and tankage are largely the fat- extracted and dehydrated residue from inedible portions of slaughtered animals and in some cases from the whole carcasses of dead animals. The protein content of meat scraps and tankage will vary from 45 to 80 per cent, according to the amount of bone contained and the amount of blood and stick added. Meat scraps of high quality are good feedstuffs. In gen- eral, however, meat scraps and other similar packing-house by-products contain a much smaller proportion of muscular tissue than do fish meals, because nearly all edible portions of meat are diverted to human feeding, while fish meals contain a large proportion of whole fish. Milk Products. — Milk products supply animal protein, but owe their 18 California Agricultural Extension Service [ Cir - 1° 8 chief value to their content of vitamin-G complex. Where there is a cheap supply of fresh skim milk or buttermilk, satisfactory results can be ob- tained with these as the only protein supplement to a grain or grain by-product ration. However, it is usually necessary to restrict the supply of water in order to induce the birds to consume enough milk. On a dry-weight basis, there is but little difference in feed value be- tween fresh milk products, semisolid milk products, and dried milk prod- ucts. The modern process of manufacture does not seem to change the quality of the nutrients, so that the value in each case depends princi- pally on the analysis of the product. Roughly, 1 pound of dried skim milk is equivalent to 10 pounds of liquid skim milk, and 1 pound of dried whey to 13 pounds of liquid whey. Semisolid milk products, provided they are of high quality, will do as well as either the fresh or the dried milk prod- ucts. On the basis of the dry-matter content, however, condensed milk products are usually far more expensive than dried products, and have no advantage over them in feeding value. If a wet milk product is de- sired, it may be made more cheaply by adding hot water to the corre- sponding dried product. There is no difference in value between sweet and sour milk ; but in order to avoid digestive troubles, the milk should be fed either sweet all the time or sour all the time. The acid itself has, contrary to general belief, no specific advantage for the bird under normal conditions. Oil-Cake Meals. — -The oil-cake meals are protein-rich residues from soybeans, coconuts, hempseed, linseed, peanuts, etc., which remain after the fat has been removed by high pressure or by extraction with a solvent. Soybean meal is a valuable protein concentrate. It requires thorough heat treatment before its full feeding value is developed. The modern expeller and hydraulic processes seem to heat the meal sufficiently for this purpose. Sesame meal and peanut meal are good feeds, containing protein of high nutritional value. Hempseed meal is high in fiber, but the protein of hempseed meal seems to be of excellent quality for poultry. Coconut meal may be employed in poultry mashes to the extent of 5 per cent in place of an equivalent quantity of grains or grain by-prod- ucts. The same applies to babassu meal which is very similar in composi- tion and feeding value. Linseed meal, because of its laxative effect, should never be added to the mash in a proportion higher than 5 per cent. Linseed meal is usually too high in price, considering its feed value, to justify its use for poultry feeding. Feeding Chickens 19 Cottonseed meal may be given similar limited usage in chick rations. Its use in laying rations is not advisable since it causes "pink white" in storage eggs. Animal vs. Vegetable Protein Concentrates. — Many vegetable pro- teins, such as those found in the grains, have a lower nutritional value than animal proteins in the form of fish meal. However, certain vegetable protein concentrates, such as soybean meal, if adequately supplemented with vitamins and minerals, seem to be nearly as high in nutritional value as animal protein concentrates. The cost of vegetable protein concentrates, per pound of protein, is usually higher than the corresponding cost of animal protein concen- trates. For example, 60 parts of fish meal and 40 parts of ground barley give a mixture containing about 45 per cent of protein. This is equal in protein content and at least equal in feeding value to any of the vegetable protein concentrates, which, therefore, must not be higher in price than the mixture to justify their use. If fish meal costs $50 a ton and barley $25, the mixture would cost $40 a ton ; and a vegetable protein concen- trate containing 45 per cent of protein would have to meet this price in order to compete. Small amounts of vegetable protein concentrates are often included in the ration to provide variety, but usually not more than 25 per cent of the animal protein should be replaced with vegetable protein for the rea- sons stated above. MINERAL SUPPLEMENTS Care should always be taken to insure sufficient consumption of min- erals. The best practice is, therefore, to include most of the necessary mineral supplements in the mash. Both growing and laying mashes will usually be deficient in minerals unless calcium phosphate, calcium car- bonate, and a small amount of salt are added. There is never any reason for paying high prices for proprietary min- eral supplements, since an adequate supply of suitable minerals can always be provided very cheaply. Minerals are present in all the feed- stuffs used for poultry. Moreover, no one mineral mixture could possibly be made to supplement even a minority of the mixed feeds in a proper way, because each formula will require an addition of different amounts of minerals. Salt. — Finely ground common salt should be added to the mash in the proportion of from 0.5 to 1.0 per cent. Salt stimulates the appetite, aids digestion, and is also required for other body processes. Too high a level of salt is injurious to birds. Phosphorus. — A common supplementary source of this element is the 20 California Agricultural Extension Service L Cir - 108 calcium phosphate furnished by bones in various forms. Growing mashes should contain not more than a total of 0.8 to 1.0 per cent of phosphorus and 1.6 to 2.0 per cent of calcium, the ratio of calcium to phosphorus be- ing about 2 to 1. A higher phosphorus content than 1.0 per cent will fre- quently cause "slipped tendons" or deformed hocks in growing birds, especially of the heavier breeds. Fish meal and meat scrap supply a great deal of phosphorus in poultry rations. Some meat scraps are so high in ground bone that they contain more than 5 per cent of phosphorus. Steamed bone meal is commonly used to supply phosphorus and is probably the best phosphorus supplement. Fertilizer bone meal cannot be recommended for feeding purposes. Only edible steamed bone meal or bone meal which has been properly sterilized should be used. Fresh green bone is rich in calcium and phosphorus but is extremely difficult to handle and feed in large quantities because it becomes easily spoiled. A further disadvantage is that an even distribution among the members of a flock is difficult to secure. Precipitated bone phosphate often contains traces of arsenic. Lots guaranteed to be free of arsenic serve well for feeding purposes but will ordinarily be found too expensive as compared with other sources of calcium phosphate. Phosphate rock has caused injury to poultry because of toxic impurities such as fluorine. There is some doubt whether all of the phosphorus in the vegetable feedstuffs is readily available to chickens. Calcium. — Besides providing phosphorus, bone meal also furnishes calcium, but usually another source of calcium has to be provided to keep the right proportion between calcium and phosphorus. Recent investi- gations seem to indicate that a calcium-to-phosphorus ratio of 2 to 1 is satisfactory for growing birds. The optimum calcium-to-phosphorus ratio for laying birds has not yet been determined. Laying birds need an additional supply of calcium for the formation of eggshells, which are principally calcium carbonate. Additional calcium is logically and com- monly supplied in the form of oystershell, limestone, calcite, etc. It is immaterial which of these forms is used, hence price should be the decid- ing factor ; but any source of calcium showing large amounts of magne- sium should be avoided. The ordinary practical ration will contain about Y 5 pound of magnesium per 100 pounds. This is ample to meet the re- quirements for this element. Limestone containing more than 5 per cent of magnesium carbonate should not be used in chick mashes because growing birds are injured by high magnesium diets. Laying birds seem to tolerate high magnesium limestones (dolomites) and marls without Feeding Chickens 21 difficulty but must consume them in large quantities to obtain enough calcium. Whenever vegetable protein concentrates are used to replace animal protein, the mineral supplements must be increased, for vegetable pro- tein concentrates have very low calcium and phosphorus content. Fig. 3. — An example of slipped tendon. The tendon of the leg at the right has slipped outwards from the normal position, which bends and cripples the leg. The leg at the left is not af- fected. Excessive amounts of calcium and phosphorus in the diet of growing birds may lead to the development of slipped tendon, or perosis. This dis- ease starts as a puffiness in one or both of the hock joints, although the bird appears normal in every other way. After about a week, the affected joint is turned away from the normal position as if dislocated (see fig. 3) . When advanced to this stage the deformity is permanent, and the bird is of very little use, since it walks with difficulty and may be ill-treated by its pen mates. Slipped tendon may be prevented, but cannot be cured. 22 California Agricultural. Extension Service [ Cir - 108 There are several causes, each of which may independently bring on the condition. If more than one cause is present, slipped tendon is even more likely to appear. Confinement on wire floors without roosts, such as oc- curs in broiler batteries, is one cause. Another is hereditary, and the heavy breeds seem to be more susceptible. A third cause is too much phosphorus, or perhaps too much calcium, in the ration. Usually slipped tendon can be prevented by reducing the amount of bone meal in the TABLE 3 Average Calcium and Phosphorus Percentages of Feedstuffs by Groups Group Whole grains — Corn, wheat, barley, oats, kafir, milo, hegari, feterita, millet, rice . Bran and middlings — Wheat bran, rice bran, rice polish, wheat middlings, wheat mill run wheat shorts Dried alfalfa products Meat scraps, 50-55 per cent protein Fish meal, sardine Fish meal, tuna Milk products, dried- Dried skim milk, dried buttermilk, dried whey Vegetable protein concentrates — Babassu, coconut, hempseed, linseed, peanut, and soybean meals. Sesame meal Limestone and oystershell Bone meal, steamed Per cent calcium Per cent phosphorus 0.03 0.33 0.09 1.20 1.70 0.22 9.00 4.50 5.00 3.00 7.00 4.00 1.30 0.85 0.30 0.65 2.00 1.60 39.00 Trace 33.00 15.00 ration, and by avoiding the excessive use of meat and bone scraps which contain large amounts of ground bone. Yet another cause is a deficiency of manganese. Computation of Calcium and Phosphorus Levels. — The best method of ascertaining the actual levels of calcium and phosphorus in poultry feeds is chemical analysis for these elements. It is frequently necessary, how- ever, to arrive at some reasonably close estimate of the percentages of these elements by calculations based upon the tables of average composi- tion. Such calculations can be accepted only as estimates, with the under- standing that feedstuffs vary in their content of calcium and phosphorus as well as in most other respects. Certain kinds of feedstuffs fall into well-defined groups according to their calcium and phosphorus content. By using the average figures for the group, rather than the individual figures for each separate feedstuff, the calcium and phosphorus levels may be calculated with somewhat less labor and with an accuracy that is sufficient for practical purposes. Feeding Chickens 23 The groups of the more common feedstuffs and their average percent- ages of calcium and phosphorus are listed in table 3. If the ration con- tains, for example, 60 per cent of whole grains, the percentage of calcium in the diet contributed by these grains is found by multiplying 60 by 0.03 and dividing by 100, to obtain 0.018. The percentage of calcium in the diet contributed by 2 per cent of bone meal would be obtained by multi- plying 2 by 33 and dividing by 100. The result is 0.66 per cent calcium. TABLE 4 Approximate Manganese Content of Feedstuffs Feedstuff Manganese content, parts per million Feedstuff Manganese content, parts per million 26 14 13 87 5 18 40 16 12 200 18 34 Oystershell 100 19 17 Rice bran 260 Salt 1 1 Soybean meal 30 Kafir Wheat 30 Kelp Wheat bran 110 Wheat middlings 100 Wheat shorts 60 Oats Whey, dried 14 Manganese. — Recent experiments indicate that manganese deficiency may sometimes occur in practical diets and cause certain deformities in embryos and slipped tendons in growing birds. Only small amounts of this element are necessary. If a manganese deficiency is suspected, it may be remedied at the cost of a few cents a ton by adding y 2 pound of man- ganese sulfate to 1 ton of mash. The manganese sulfate may be dissolved in a quart of warm water and premixed in a small portion of the mash, or it may be mixed with the limestone or bone meal and the mixture added to the mash. Manganese must not be regarded as a cure-all that will rectify a poorly formulated mash or completely compensate for poor brooding conditions. The approximate values for manganese in feedstuffs are reported in table 4. Other Minerals. — A practical poultry diet will provide ample amounts of such minerals as iron, copper, and iodine, which are required only in minute quantities. Experiments on the addition of supplements of these mineral elements to practical diets have not shown any advantage to be derived. Iron and copper appear in sufficient amounts in nearly all feed- 24 California Agricultural Extension Service [Cir. 108 stuffs. Iodine is supplied by marine products such as fish meal and oystershell. Charcoal. — Charcoal is frequently recommended and used as a supple- ment to poultry rations. There is no clear experimental evidence to show an advantage in charcoal feeding, nor is there any to indicate that it does any harm. The adsorbing power of charcoal has been much overempha- sized. Even if present, the adsorbing power would be of questionable value. Grit. — Grit should be given to poultry at all times, in order to enable the birds to grind and utilize the ordinary coarse feeds in an efficient way. Hard grit, such as pebbles or granite grit, will serve such a purpose better than the softer limestone grit and will not upset the mineral bal- ance of the ration. Hard grit is insoluble and is not intended to take the place of mineral supplements. Water. — An abundance of clean, palatable water is of utmost impor- tance. The requirement for Avater is greatly increased in hot weather. Under average conditions, 100 laying hens will consume about 125 gal- lons of water a month. Restriction of water intake by any means is one of the surest ways to obtain poor results with poultry. Deprivation of water for even a short period will give birds a setback from which recovery may take several days. VITAMIN SUPPLEMENTS In order to make the poultry ration complete, certain vitamin supple- ments must be included. The vitamins for which definite provision must be made are A, D, and the G complex. Feeds Supplying Vitamin A. — Vitamin A is commonly supplied by fresh greens such as alfalfa, clover, kale, chard, lettuce, Sudan grass, green barley, green oats, lawn clippings, and young corn. It may be sup- plied equally well by dried greens or yellow carrots. The poultryman should plan ahead for a regular everyday supply of from 5 to 6 pounds of green feed for every 100 birds. More should not be fed, since an excess of green feed makes the egg yolks dark. Tests of various fresh greens as a source of vitamin A have shown no great difference in value. Therefore the green feed which can be procured most economically at any particu- lar time or place should be used. Alfalfa can generally be depended upon during a large part of the year. It should preferably be cut when young and tender because the woody stems of the mature plant are less digestible. The stems are low in vitamins. Alfalfa meal, as used in the mash formulas of this circular, refers to good-quality meal with less than 28 per cent fiber. In many sections of California, kale is depended upon for green feed. Feeding Chickens 25 Some poultrymen use the whole plant and run it through a feed chopper. A better practice probably is to feed the leaves only, because they are the most valuable part, and because the plant under those conditions may give continued growth and production. The preparation of green feed by the sprouting of grains is inevitably accompanied by a loss of feed value, since a destruction of the protein and carbohydrate sets in almost simultaneously with the beginning of germination. Without considering the cost of labor, the sprouting of grains for the purpose of supplying fresh greens for poultry is therefore an uneconomical practice. It should further be remembered that all im- perfect or injured kernels when prepared for sprouting are greatly exposed to molds, some of which may be very toxic. Precautions should be taken to avoid access of the laying hens to cheeseweed, or mallow, for this plant, when eaten by hens, has recently been shown to be a common cause of the "pink white" deterioration of storage eggs. Cheeseweed is often found in poultry districts, along road- sides and at the edges of fields. It is also likely to be present in products such as dried alfalfa when these are not kept free from weeds. "Pink white" deterioration will also be caused by other plants or plant prod- ucts, notably tree mallow (Lavatera assurgentiflora) , hollyhock, and cottonseed meal, or kapok meal. Alfalfa meal and alfalfa-leaf meal provide more convenient vitamin-A supplements for poultry than do the fresh greens. If cured under proper conditions, the vitamin-A content of the plant is fairly well conserved. The ideal conditions are rapid drying without long exposure to the sun. Quick curing will yield a product of bright-green color. Products which have lost their green color and look yellow or brownish, should never be used. Still another source of vitamin A has been found to be yellow carrots. They have not been popular as a poultry feed because there is a common belief that birds do not relish them. Birds have to become used to any new feed but do so quickly. Yellow carrots can sometimes be produced more cheaply than fresh greens and also have the advantage that they can be stored for a time. However, they are not so good a source of ribo- flavin as greens. The yellow pigment of carrots is carotene, which does not color egg yolks. Fish oils are primarily used as sources of vitamin D but they also provide vitamin A when fed in freshly mixed feeds. They cannot eco- nomically be used as a complete substitute for the vegetable sources of vitamin A. The work of several experiment stations agrees fairly well with a 26 California Agricultural Extension Service [ Cir - 108 figure of about 2,100 units 7 of vitamin A per pound of diet as adequate for egg production and good hatchability. If this figure is raised to 2,500 units to add an additional margin of safety, a suitable working basis re- sults for providing vitamin A in laying mashes. Mashes to be used with an equal proportion of scratch grains should contain at least 5,000 units of vitamin A per pound. In these recommendations the vitamin A that may be in the scratch grains has not been considered. Table 5 gives the vitamin-A content of certain supplements which provide this vitamin. TABLE 5 Approximate Vitamin-A Content of Certain Feedstuffs Feedstuff Units of vitamin A per pound Remarks Yellow corn 3,180 75,700 151,400 40,000 14,000 1,360,000 50.0 per cent corn in the mash will supply only 1,590 units per pound 7.0 per cent in the mash will supply about Alfalfa meal, containing 10 milligrams Alfalfa meal, containing 20 milligrams 5,300 units per pound 3.5 per cent in the mash will supply about 5,300 units per pound 1.5 pounds per 100 birds per day will supply about 600 units per bird 3.5 pounds per 100 birds per day will supply about 500 units per bird 0.4 per cent in the mash will supply about 5,400 units per pound, when freshly mixed Fortified fish oil, 3,000 A Young chicks require about 700 units of vitamin A per pound of feed. More than this is supplied by 1 per cent of a good grade of alfalfa meal containing 20 milligrams of carotene per 100 grams. Consequently, vita- min A is only a minor problem in chick feeding. The amounts of fresh and dried greens recommended in chicken rations are determined primarily by their value as a source of riboflavin rather than as vitamin A. Feeds Supplying Vitamin D. — If an abundance of direct sunlight is available, no further provision of vitamin D in the diet may be needed. As a precaution, however, additional vitamin D may well be provided in all rations. The most practical way to do this is to use a fish oil, such as sardine oil or cod-liver oil. Some of the less abundant fishes yield liver oils which are enormously potent sources of vitamins A and D. These oils are used in the manufacture of certain fortified or high-potency oils, which often consist of a mixture of fish oils blended to reach a definite 7 The vitamin-A unit referred to in this publication is that denned in the United States Pharmacopeia, XI (1936). It is identical with the International unit by defi- nition. Feeding Chickens 27 potency. Since high levels of oil are undesirable, such blends have an advantage of being effective in smaller amounts than ordinary cod-liver oil or sardine oil. Vitamin D is needed by young stock that spend a con- siderable part of the time indoors in the early part of the year because of cool weather or rain. In most sections of California it is therefore always advisable to feed some form of vitamin D to young chicks during the first two months of their life. Older birds also need this additional supply of vitamin D during periods of very heavy production and late in the laying season, when thin eggshells often give evidence of poor cal- cium utilization. The greatest requirement for vitamin D is found in the ration of breeding hens in order that eggs of high hatchability may be produced. Sources of vitamin D, such as fish oils, used in poultry feeding should always be standardized by testing with chicks, for there is no other known way of ensuring their adequacy. Biologically tested oils usually are pro- vided with a statement of the number of chick units 8 of vitamin D per gram of the oil. Chicks, in the absence of direct sunlight, require at least 20 chick units of vitamin D per 100 grams of feed, so that a 100-D oil should be fed at the rate of at least 0.20 per cent of the feed and a 400-D oil at the rate of at least 0.05 per cent. The oil manufacturers usually in- crease these levels in order to provide a margin of safety because a chick receives very little direct sunlight during the first 2 or 3 weeks of its life. Older chicks that are continually outside commonly receive enough sun- light to supply their complete vitamin-D requirements. In the complete absence of direct sunlight, laying hens require about 80 chick units per 100 grams of feed for maximum hatchability. If equal parts of mash and grain are fed, this represents 1.60 per cent of 100-D oil or 0.40 per cent of 400-D oil in the mash. Actually the birds will usually receive a con- siderable amount of vitamin D in the form of direct sunlight. Vitamin D is sufficiently stable so that fish oils can be mixed into mashes without any danger of loss of any vitamin D if the mash is used within a few months. Feeds Supplying Vitamin-G Complex. — The two factors of the vita- min-G complex which are the most important in poultry diets are ribo- flavin and the filtrate factor. The cereal grains are poor sources of ribo- flavin, and many of the protein concentrates are only slightly better. Hence fresh and dried greens, which supply riboflavin, are of great im- portance in feeding chickens. Of course, green leaves supply other vita- 8 The vitamin-D chick unit referred to in this publication is that determined accord- ing to the tentative procedure of the Association of Official Agricultural Chemists in which it is assumed that 1 U. S. P. unit of vitamin D (in the United States Pharma- copeia Reference Cod-Liver Oil) equals 1 A. O. A. C. chick unit. 28 California Agricultural Extension Service [ Cir - 108 mins, such as vitamin A (p. 24). So great is the requirement for riboflavin that fresh and dried greens may fail to supply the entire need, particu- larly in the case of chicks and breeding hens. Consequently, additional sources of riboflavin, such as milk or whey, are commonly used in poultry rations. Pure dried yeast is a very good source of riboflavin, but it is usually too expensive, and unfortunately some of the cheaper "feed yeasts" are so heavily diluted with cereals that their riboflavin content TABLE 6 Average Eatings of Common Feedstuffs of Good Quality for Riboflavin and Filtrate Factor Feedstuff Riboflavin value Filtrate-factor value Cereal grains: barley, milo, Wheat bran and rice bran . corn, wheat, oats 0.4 1.0 0.5 0.5 0.3 5 to 8 2.0 (fresh weight) 12.0 6 to 10 6 to 12 1.0 1.0 0to3 12 to 18 10 to 18 Very low 0.0 0.0 0.7 1.8 0.8 Sardine meal 0.2 Meat scrap 0.2 Alfalfa meal, good grade Young fresh greens 1 to 3 Very low 3.0 2.5 4.0 4.0 1.0 Cane molasses, liquid or dried 6.0 8.0 15.0 Low-grade "feed yeasts" Low 0.0 Mineral supplements 0.0 is very low. Liver meal is a good source, provided it has not been mixed with other packing-house by-products, such as tankage, which contain little or no riboflavin. The filtrate factor (antidermatitis vitamin) has a distribution in nat- ural feeds different from that of riboflavin, and a deficiency of it is less likely to occur because of its presence in the cereal grains and in bran. The distribution of riboflavin and the filtrate factor is shown in table 6. The data in table 6 are by no means exact, since different samples of the same feedstuff may vary greatly in their content of the vitamin-G complex. In order to find out whether a particular ration has sufficient ribo- flavin, the percentage of each feedstuff used in the ration should be multi- plied by the riboflavin value of that feedstuff as given in table 6. The value for the ration as a whole will then be the sum of the products for Feeding Chickens 29 each feedstuff. The filtrate-factor value of the ration is calculated in the same way. The method of calculating is shown in table 7. A diet for chicks should have a total riboflavin value of about 100, and a filtrate-factor value of 90 or more. The ration analyzed in table 7 more than fulfills these requirements. A breeding ration (mash and scratch grains) should have a total riboflavin value of at least 125. The filtrate-factor value of a breeding ration does not seem to need so much attention because enough for egg TABLE 7 A Sample Calculation of the Eiboflavin and Filtrate-Factor Values of a Chick Eation Feedstuff Per cent in ration Per cent in ration X riboflavin value Per cent in ration X filtrate factor value Cereal grains 54.0 15.0 15.0 4.0 8.0 3.5 0.5 22 15 8 32 52 38 Wheat bran 27 Sardine meal Dried skim milk Alfalfa meal 3 10 13 Minerals Fish oil Total 100.0 129 91 production and hatchability is usually supplied by the cereal grains and their by-products. It is recommended, however, that the filtrate-factor value of the mash be maintained at least at 100 in order that the chick may have a good reserve store of the filtrate factor when hatched. A laying ration (mash and scratch grains) does not need to contain quite so much riboflavin as a breeding ration, because the requirement for egg production is not so great as the requirement for hatchability. A riboflavin value of about 100 in the total ration is probably sufficient for egg production. The filtrate-factor requirement for egg production seems to be well provided by ordinary rations. The riboflavin values in table 6 may be converted to micrograms per gram of feedstuff by multiplying the riboflavin value by 2.7. This is mentioned because it appears that the microgram of riboflavin will be the unit commonly used in the near future. Riboflavin and the filtrate factor are stable vitamins and do not dis- appear from the mash if it is used within a reasonable time. Prolonged exposure to sunlight and dew in curing alfalfa results in a loss of some of the riboflavin. 30 California Agricultural Extension Service [ Cir - 108 FEED FORMULAS FEEDING LAYING HENS Poultry feeding is properly based on grains and their by-products as the main source of nutrients, with such additions as are necessary to complete the ration. The grains used in building up a poultry ration should be those which are available at a reasonable cost, because starch, TABLE 8 Laying-Mash Formulas* Laying mash 1 Laying mash 2 Laying mash 3 Laying mash 4 Ingredients Per cent Pounds per ton Per cent Pounds per ton Per cent Pounds per ton Per cent Pounds per ton Constant ingredients: Fish meal (65 per cent crude protein) Meat scrap (50 per cent 12.5 5.0 7.5 2.0 2.0 1.0 1.0 16.0 30.0 10.0 13.0 250 100 150 40 40 20 20 320 600 200 260 10.0 5.0 7.5 5.0 2.5 2.0 1.0 1.0 16.0 30.0 10.0 10.0 100.0 200 100 150 100 50 40 20 20 320 600 200 200 2,000 7.5 7.5 5.0 7.5 1.0 2.0 1.0 1.0 16.0 30.0 10.0 11.5 150 150 100 150 20 40 20 20 320 600 200 230 15.0 10.0 4.0 2.0 2.0 1.0 1.0 16.0 20.0 29.0 300 Dried skim milk, dried buttermilk, or dried 200 Soybean meal, sesame meal, hempseed meal, or peanut meal 80 40 Ground limestone or 40 Salt 20 Fish oil, 100-Df 20 Variable ingredients: 320 Ground yellow corn 400 580 Total . . 100.0 2,000 100.0 2,000 100.0 2,000 * Intended to be fed with approximately equal quantities of scratch grains. t Or 400-D oil, 0.25 per cent (5 pounds per ton). the main constituent of value in grains, is essentially the same whether obtained from one grain or another. Consequently, there is no "best" grain for poultry. The exact combination of grains is of only slight im- portance. If a variety of grains or grain by-products can be used without add- ing too much expense to the ration, the variety has one advantage. A change of any one constituent of a ration composed of three or more grain Feeding Chickens 31 by-products can be made without danger of detrimentally affecting the birds. On the other hand, when one grain has been fed as the only grain, a change to a new grain may temporarily throw the birds off feed. For the sake of convenience, the laying mash is commonly formulated in such a way as to make the proportions of the different nutrients about right when grains and mash are fed in equal amounts. In such case, a certain amount of ground grains and grain by-products must always be added to the concentrates in order to establish the proper protein con- tent. Table 8 gives formulas for satisfactory laying mashes. TABLE 9 All-Mash Ration for Laying Hens Ingredients Per cent Pounds per ton Fish meal (65 per cent crude protein) 6.0 2.5 5.0 8.0 30.0 25.0 20.0 1.0 1.5 0.5 0.5 120 Dried skim milk, dried buttermilk, or dried whey 50 Alfalfa meal 100 Wheat bran 160 Ground barley 600 Ground corn 500 Ground wheat 400 Bone meal 20 Ground limestone or oystershell Salt 30 10 Fish oil, 100-D* 10 Total 100.0 2,000 * Or 400-D oil, 0.125 per cent (2.5 pounds per ton). Any of the laying-mash formulas in table 8 will give satisfactory re- sults when fed with equal amounts of grain. Calcium carbonate in the form of coarse limestone grit or oystershell should be provided sepa- rately in addition to any of the mashes used. These mashes should be kept before the birds at all times. It is advisable to feed just enough mash to last about 24 hours, since a daily provision of fresh mash will lead to better feed consumption than if the mash is renewed only every few days. Mash should not be exposed to direct sunlight during feeding because sunlight will rapidly destroy vitamin A and riboflavin in the top layer of the mash, which is the portion from which the birds eat. The variable mash ingredients in table 8 consist of the grains and grain by-products. Those suggested in these formulas will work well in the proportions in which they are given, but other grains or different pro- portions of grains will do equally well. For example, rice bran can be employed in place of a portion of the wheat bran ; wheat middlings in place of wheat and bran ; kafir, milo, and other sorghums in place of corn ; oats in place of barley, etc. 32 California Agricultural Extension Service [Cir. 108 The fish oil used should be a biological oil of tested and guaranteed potency for poultry. If a 400-D oil is used, guaranteed to contain 400 chick units per gram of oil, 1 quart of 400-D oil may be used in place of 1 gallon of 100-D oil. One pint of oil weighs almost 1 pound, hence liquid measure can be used when more convenient. The oil should be first mixed TABLE 10 Chick-Mash Formulas' Chick mash 1 Chick mash 2 Chick mash 3 Ingredients Pei Pounds Per Pounds Per Pounds cent per ton cent per ton cent per ton Constant ingredients: Fish meal (65 per cent crude protein) 12.5 250 7.5 150 15.0 300 Dried skim milk, dried butter- milk, or dried whey 5.0 100 5.0 100 2.0 40 7.5 150 7.5 150 10.0 200 Meat scrap (55 per cent crude protein) 6.0 120 Bone meal 1.0 20 Ground limestone or oystershell 2.0 40 2.0 40 2.5 50 Salt 0.5 10 0.5 10 0.5 10 Cane molasses 3.0 60 Fish oil, 100-Dt 0.5 10 0.5 10 0.5 10 Variable ingredients: Wheat bran 16.0 320 16.0 320 20.0 400 Ground yellow corn 25.0 500 25.0 500 20.0 400 Ground wheat 15.0 300 15.0 300 10.0 200 15.0 300 2,000 15.0 300 2,000 16.5 100.0 330 Total 100.0 100.0 2,000 * If used for battery broiler production these mashes shovdd be supplemented with manganese sul- phate, }/% pound per ton of mash. t Or 400-D oil, 0.125 per cent (2.5 pounds per ton). with the wheat bran or a part of the ground grains, and the oil-grain mixture then thoroughly distributed throughout the mash. On chemical analysis, these mashes will show a crude-protein content varying with the different feed commodities included. With ingredients as listed in the formulas, the crude-protein content will be about 19 per cent. In view of the wide variation in nutritional value and digestibility of the various feed proteins, too much emphasis should not be put on the exact crude-protein analysis. A poor feed may show considerably higher protein content than another to which it really is inferior. Mashes should not be too fine but should be ground sufficiently fine to guard against disproportionate selection of the ingredients by the birds eating the mash, so that the portion of the mash consumed by any bird Feeding Chickens 33 will have the same composition as that prescribed in the formula of the mash. If the mash is too fine the birds will not eat it readily, and there may be impaction of feed in the mouth with accompanying irritation or necrosis in severe cases. Scratch grains can be fed cracked or whole. Since the birds have an efficient grinding apparatus of their own there is no economic advantage in grinding scratch grains. Scratch grains to be fed with these mashes for laying hens may consist of such combinations as equal parts of wheat, milo, and barley, or 2 parts of barley and 1 of corn, or a variety of many other possible combinations. To feed the grain from hoppers is more sanitary than to scatter it in the litter or on the ground. All-mash laying rations are merely laying-mash formulas to which more ground grains and grain by-products have been added in the pro- portion of 1 part of added grains and grain by-products to 1 part of mash. All-mash rations simplify the work of feeding, but they increase the cost of the feed because of the necessity of grinding the added grains. There is at present no good evidence, other than cost, on which to base a statement concerning the relative merits of mash and scratch feeding as compared to all-mash feeding. As an example of a suitable all-mash ration the formula in table 9 is presented. If the mash is to be fed to birds in total confinement the amount of fish oil should be 0.8 per cent of 100-D fish oil (2 gallons per ton) or 0.2 per cent of 400-D fish oil (2 quarts per ton). This mash is suitable for use in laying batteries provided additional limestone or oystershell is made available in separate hoppers. The total feed consumption of a Leghorn hen per year will be about 80 pounds but will vary with digestibility of the ration and the production of the bird. Mash and grain consumption are about equal over a period of a whole year, but will vary at different times, according to the rate of production. (See table 11.) FEEDING GROWING BIRDS There is no fundamental difference between a laying ration and a grow- ing ration for poultry because both have to furnish essentially the same requirements : protein, energy, vitamins, and minerals. The protein requirements of the rapidly growing chick (that is, up to three or four months of age) are higher than those of the laying hen. The protein level for baby chicks during the first 4 to 6 weeks should be 19 to 20 per cent of the ration. The protein requirements decrease as the rate of growth progressively slows down. At the same time carbohydrate requirements increase in direct proportion to the increasing size of the 34 California Agricultural Extension Service [ Cir - 108 animal. The calcium requirement for growth is less than that for egg production. In the case of growing birds, uniformity of requirements makes it more advisable to provide a single feed mixture that furnishes the different constituents in the proper proportions. For this reason chicks should be started on an all-mash feed, and whole grain should be omitted until after the fourth week, when the habit of eating mash has been well established and growth is well under way. The additional feeding of grains should be started very gradually, the amount at first being not more than about one-fourth of the mash consumed. The proportion of grains to mash may be slowly increased until, at about three months of age the birds receive equal parts of mash and scratch grains. The formulas in table 10 for chick starting mashes are recommended. They may also be used as grow- ing mashes with scratch grains fed after the fourth week. Additional limestone grit or oystershell should not be fed to chicks because the mash is designed to contain adequate amounts of calcium for growth, and additional calcium may be injurious. In feeding chicks, the mash should always be kept before them in open hoppers beginning as soon as they are placed under the brooder. One 4-foot hopper accessible on both sides should be provided for each 100 chicks. Additional hopper space will be required as the chicks grow older. The grains should also be hopper-fed and may be kept before the chicks at all times after they are three months old. 9 The amount of grain fed, however, should be restricted to a quantity not more than that of the mash consumed. Feed consumption by chicks will vary with the palatability and ade- quacy of the ration being fed, as well as with the breed of chicks and brooding conditions (see table 11). FEEDING BREEDING HENS The production of hatching eggs is ordinarily obtained by the same feeding methods as in the production of commercial eggs. Frequently birds from which the eggs are collected for hatching purposes are fed less protein in order to keep production down to some extent. This practice is probably harmful. Better hatching eggs are obtained when sufficient riboflavin is sup- plied, as by feeding larger amounts of milk or whey, by including plenty of good alfalfa meal in the mash, and by the supplementary feeding of fresh greens. It is always advisable to include fresh greens in breeding- stock rations. However, satisfactory results can probably be obtained 9 Persons interested in more detailed information about brooding are referred to : Newlon, W. E., and M. W. Buster. Brooding and pullet management. California Agr. Ext. Cir. 28:1-23. Revised 1936. Feeding Chickens 35 from the use of some form of dried alfalfa if used in sufficient quantities. The laying-mash formulas given in table 8 will serve well as breeding mashes if ample fresh greens are also fed. In the absence of fresh greens, about 2.5 per cent more of some dried-milk product or of good quality dried alfalfa will probably suffice. It is suggested that the level of fish oil used be doubled. About 2.5 per cent of cane molasses may also be added. TABLE 11 Approximate Consumption or Feed by Chickens Pounds per 100 birds Basis Sex Age, weeks White Leghorns Rhode Island Reds and Plymouth Rocks < Both sexes . . . Females only Female - 2 4 6 8 10 12 16 20 24 28 32 36 28 100 235 410 550 730 1,190 1,690 2,240 2,820 3,420 4,030 7,670 21 30 105 250 440 590 800 1,380 2,020 2,740 3,500 4,250 5,000 8,760 Female 24 Vitamins are of special importance in breeding rations. A few cents of extra expense per sack of mash to ensure more adequate vitamin levels will repay the poultry breeder many times over in higher hatchability and greater percentage of top-grade, vigorous chicks. Such chicks will have an ample reserve of vitamins which will tide them over the early periods of growth during which the amounts of essential vitamins ob- tained in the diet may be insufficient. Chicks with good reserve stores of essential vitamins have far less chance of developing any of the trouble- some early nutritional diseases resulting in poor growth, curled-toe paralysis, or rickets. FEEDING MOLTING BIRDS Ordinarily all birds in a flock are not molting at the same time. Special consideration in the feeding of molting birds therefore is effective only if the molters are separated from the other birds. In this case the molters, if they have the proper weight, do not need so much feed as laying birds, but they should be fed well. 36 California Agricultural Extension Service [ Cir - 108 FEEDING TABLE POULTRY The feeding of table poultry involves two main problems : first, the rapid growth of young stock to the finishing stage, and second, finishing by use of special diets during a short period of time to produce birds of the broiler, fryer, and roaster classifications. Young birds in the period of rapid growth will not respond satisfac- torily to the so-called "fattening" diets but will merely keep on growing to the extent that the diet permits. Feeding during the early stages of a meat bird's life should be designed primarily for the objectives of health, vigor, proper bone development, and rapid growth. This can be achieved only by completely balanced mashes such as those that have been given. Birds raised for meat purposes should not be given grains in addition to the chick mashes until they are at least 8 weeks old, and preferably 10 weeks old, if the maximum rate of growth is desired. Finishing or "fattening" feeds are designed for the improvement of color, texture, and flavor of the flesh of table poultry. Such feeds are not complete in all dietary respects and can be used only for a limited period of from 1 to 2 weeks, according to the condition of the bird. They are commonly composed of ground grains supplemented with liquid milk or dried milk plus water to make a mixture of the consistency of a thick soup. A certain proportion of animal protein is essential in producing eco- nomical gains during a finishing period. The most satisfactory source of animal protein for this purpose is some form of milk or buttermilk, either liquid, condensed, or dry. The liquid, unconcentrated milks contain only about 10 per cent of solid matter and must be used in larger quantities in accordance with their lower solids content. A part of the milk may be replaced with a good-quality meat scrap or fish meal. The total animal protein content of the finishing feed should be at least 5 per cent, and where meat scrap or fish meal are used, their proportion should be com- puted on the basis of their approximate protein content. For good results, at least 5 per cent of dried milk in the feed should be retained. The dried milk may be partially replaced by fluid milk. The following is an example of finishing-feed formulas : ° Pounds Ground yellow corn 100 Ground whole barley 100 Ground oat groats or oatmeal 50 Dried skim milk 50 Water to mix to the consistency of a thick soup The mixture is commonly fed from wooden troughs, two or three times a day, as much as the birds will completely clean up at a feeding. It is Feeding Chickens 37 1 M >> -a o_ i « a 03 T»< CO .-< »-< •*»< •**< l>- © © i-l -l © N f f T(i © © « > 5 -d 03 HOOHN OOHNMC"5*«5lOU3 d u o 03 o co 73 o3NM ooohnnnmmm T3 035! HN00113H*O^!DN ooohnmmmmm o -G 02 o CO 0>— . II Hocm