UNIVERSITY OF CALIFORNIA COLLEGE OF AGRICULTURE AGRICULTURAL EXPERIMENT STATION CIRCULAR No. 271 October, 1923 BROODING CHICKS ARTIFICIALLY BY J. E. DOUGHEBTY and S. S. GOSSMAN CONTENTS pAGE Building the brooder house 2 Good ventilation without drafts 2 Sunlight 5 Safety from fire 6 Temperature flexibility 6 Ample heat capacity 7 Economy of heating 9 Dependable heating system a necessity 10 Simplicity and durability of construction 12 Ease in cleaning 12 Convenience of operation 13 Size of hover 13 Scratching space outside the hover 14 Toe picking 14 Size of the pen 15 System of yarding 16 Summer shade 19 Feeding young chicks 20 First care of chicks 20 Feeding milk 21 Milk treatment for coccidiosis 21 Feeding grain 22 Changing from chick to growing grains 24 Feeding mash 24 Green feed 25 Crowding 26 Separation of sexes 26 Chicks piling up 26 Teaching chicks to roost 27 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION BUILDING THE BKOODER HOUSE A brooder house designed to brood chicks or turkey poults arti- ficially, should fulfill certain requirements if satisfactory results are to be obtained. These requirements should not make the construction more complicated nor add to the cost, but should facilitate the rearing of strong, thrifty stock. In the following pages these essentials are discussed in detail and the construction of brooding houses that will best embody them under California conditions is described. Since the heating system is an inseparable part of a brooder house, and is often built in, it must be considered in relation to the design of the house. Due consideration is accordingly given to this problem. Fig. 1. — This type of open front colony house makes an excellent brooding and rearing house. The house shown is 8' x 8' in size and of knock-down con- struction, but it may be built wider and any length desired. Good Ventilation Without Drafts. — Pure fresh air is even more important for poultry than for larger farm stock. The body tempera- ture of poultry is several degrees higher than that of other farm animals; their digestive system functions more rapidly, and oxygen being indispensable to the assimilation of food, the respiration must be increased to meet this need. It is therefore, of vital importance that the system of ventilation used in the brooder house be such as will rapidly remove the stale, vitiated air, charged with carbon dioxide from the chicks' lungs, with lamp fumes (if a blue flame coal-oil brooder stove is used), and with odors from the droppings. Close con- finement in poorly ventilated quarters soon saps the vitality of growing chicks, retards their growth, and increases the death rate. Combined Circular 271 J brooding CHICKS ARTIFICIALLY 3 with the heavy feeding of concentrated rations, such conditions are also conducive to leg weakness and other ills. The open front house of limited height, equipped with curtains, (fig. 1) represents one of the simplest systems of effective ventilation. Another method which is desirable for larger brooding houses is the King System. 1 In this system, fresh air is taken in near the ceiling and the stale air is withdrawn through ventilating shutes extending from about 18" above the floor to a point sufficiently higher than the highest part of the roof to provide effective suction. Good ventilation of the brooder house itself does not necessarily insure a sufficient ventilation of the hovers, unless these are so con- structed as to permit a reasonably free circulation of air. In hovers equipped with muslin or canvas curtains which hang close to the floor and greatly restrict the circulation of air, sufficient ventilation is practically impossible, even when electric or hot water heat is used, neither of which vitiates the air as does an oil heater. This seems to be especially true with a type of electric hover tested at this Station, which depends for ventilation on the natural diffusion of air in and out of the hover through the curtains. Electric hovers are very sensi- tive to temperature changes and exact in temperature regulation. There is no surplus heat given off to stimulate air circulation and cause the chicks to spread out toward the edges of the hover where the air is fresher ; or even to sleep with their heads sticking through the curtain slits into the cool outer air of the room and their bodies inside and warm, as commonly occurs with hovers heated by oil or water. In electric hovers of this type the beat from the bodies of the chicks added to that from the coils, soon heats the hover to the point where the thermostat cuts off the current. There is no surplus heat to cause the chicks to spread out toward the outside and they remain well inside the hover where the accurate regulation keeps the temperature just comfortable. As a result, they may not get enough fresh air and their vigor is impaired. In such brooders, moreover, the moisture thrown off with the air exhaled by the chicks is not carried away, but adds to the humidity of the air in the hover. This humidity may increase to a point where moisture is precipitated and the chicks arc said to " sweat/ ' The droppings do not dry out but remain moist and are tramped into and absorbed by the litter, forming a damp, foul-smelling mat of manure and straw which must be cleaned out every day if the hover is run at full capacity. i Originated by Professor F. H. King of the University of Wisconsin and described in his book, "Ventilation for Dwellings, Rural Schools and Stables." Mrs. F. H. King, Publisher, Madison, Wisconsin. UNIVERSITY OF CALIFORNIA EXPERIMENT STATION Unless a hover has a positive system of fresh air ventilation, it should not sit so close to the floor as to restrict a free circulation of air beneath. Curtains, if used, should hang at least one or two inches above the floor at first and be gradually raised higher as the chicks become older and stronger. With oil and gas brooder stoves which discharge the products of combustion directly into the air of the hover, the lower edge of the galvanized iron canopy should be not less than four inches above the floor and curtains should not be used. Fig. 2. — Hot water brooding system in which the hovers B are heated and ventilated by heated air drawn from the walkway C. The passage of the air into the adjustable opening controlled by door A, up through the chamber heated by the hot water pipes and into the hover B is indicated by arrows. Poultry keepers are realizing more and more the value of effective ventilation in promoting the rapid, hardy growth of chicks and greater numbers of brooding systems which combine with the heat supply a positive method of ventilation of the hover are being installed each year. Figure 2 illustrates a hot water system using this method of fresh air heating. Fresh heated air is discharged directly into the hovers through intake openings with manually operated doors which control the amount of fresh warm air entering each hover. This arrangement also permits a maximum of flexibility in temperature regulation under the hover, because the volume of fresh heated air entering any hover can be controlled. For chicks less than a week old the shutters may be kept wide open. They can then be closed grad- ually from week to week, according to the coldness of the weather. Chicks require less heat and spend less time under the hover, even at night, as they grow larger and stronger. Circular 271] BROODING CHICKS ARTIFICIALLY In the case of electric and oil heated hovers, the fresh air can be introduced through ducts or a false floor with fresh air intakes (fig. 3). The fresh air is then carried into the hover through a galvanized iron tube about four inches in diameter located in the center of the hover and extending from the floor to within a few inches of the top. The heating coils may be located in the false floor to heat the air before it enters the hover or may be placed in the top of the hover to heat the air as it is discharged into these heating coils. Fig. 3. — Electric hover with positive system of ventilation. Arrows show how fresh air enters under the false floor and passes into the hover. Brooder houses with walkways and wire mesh partitions are very apt to be drafty. The opening of windows in the walk-way while chick exits on the opposite side of the house are open, may set up strong air currents along the floor of a brooder pen and chill the chicks. Floor drafts being very detrimental, the location and con- struction of all openings, such as chick doors, and ventilating windows, should be carefully considered in erecting a brooder house. Sunlight. — Sunlight instills warmth and cheer into the atmosphere in cool weather; it increases the illumination within a brooder house; it is Nature's most effective destroyer of germs. Intense sunlight should not strike directly on the floor of a brooding pen, however. b UNIVERSITY OF CALIFORNIA EXPERIMENT STATION because young chicks have a tendency to bask in warm patches of sunshine and become inactive and sleepy instead of keeping active and busy. An adjustment of the curtains or an application of Sapolio or Bon Ami on the window glass through which direct sunlight strikes the floor, will prevent these conditions. Safety From Fire. — Fire risk should not be overlooked in pur- chasing and installing brooder heating devices. In constructing home- made brooders, especially, the fire risk involved is not always properly appreciated and taken care of. As a result, costly fires occur annually. Fig-. 4. — Two views of hovers heated by overhead hot water pipes. Increased ventilation is obtained with style of hover shown by first removing the front, and later the rear, burlap curtains. Boosts are placed on top of hover when the chicks are being taught to roost. Perhaps one of the greatest advantages that can be urged in favor of the hot water system of heating is its very great safety from fire, provided the heater is installed with due care. With this system there is only one fire and it can be readily enclosed in a fireproof compart- ment. With hovers using open flame oil burners, on the other hand, the fire risk is much greater. If the burners are intelligently handled and kept clean the fire risk is comparatively small, but such burners must not be neglected. Ample precaution against fire is the cheapest possible fire insurance. Temperature Flexibility. — Temperature flexibility refers to regu- lation of temperature of any given hover independently of any other hover. Chicks need less and less artificial heat as they grow larger and stronger. Keducing the hover temperature rapidly, without mak- ing the chicks uncomfortable, stimulates strong, quick growth. Too high temperatures tend to reduce the vitality of growing stock and develop ' ' hot-house chicks. ' ' One of the most serious defects of the "overhead" hot water pipe system (fig. 4) in which pipes extend through the hovers above the Circular 271] brooding CHICKS ARTIFICIALLY 7 chicks, is the impossibility of regulating the temperature of each hover independently to meet the needs of chicks of different ages. Since all of the hovers are heated by the same flow and return pipes, the tem- perature in each hover is the same as far as the heat radiated by the hot water pipes is concerned. It is only by means of some expedient such as removing the side curtains or raising the hovers higher from the floor to increase ventilation, that the temperature in any given hover can be decreased as the chicks grow older. A hot water system of this type has the advantage, however, of being the simplest and the least expensive heating device that can be installed in a permanent brooder house. If the design of the hovers is such that the tempera- ture can be effectively regulated by increasing or decreasing the ventilation, excellent results will be obtained. To overcome the failure of the ' ' overhead ' ' pipe system to govern the temperature of each hover independently by regulating the heat supplied to it, other hot water heating pipe systems have been devised. In these later systems (fig. 2, page 4) the pipes are enclosed in an insulated box or chamber below the hover floor level. Ventilator intakes in the lower part of this chamber admit fresh air which is heated as it passes up through the pipes and is then conveyed in sepa- rate ducts to the hovers. The temperature of each hover is regulated by adjusting a shutter on the outlet end of the pipe or duct carrying the fresh heated air to that hover. This system has a further advantage of positively ventilating each hover by the introduction of fresh warm air. 2 It is, however, rather costly to install. Ample Heat Capacity. — The ease with which correct temperature conditions can be maintained under the hover will largely depend upon the cubical content of the brooder pen, the heating capacity of the heater used, and the coolness of the weather. The investigations of this Station show that the larger and more open a brooder room is, the more rapidly the air of the room absorbs and dissipates the heat from the hover. To maintain a sufficiently high hover temperature under such conditions in winter and early spring, a larger fire is required and more fuel consumed. In a brooder room of a certain volume, a two-pipe (one inch pipe) hot water system might supply enough heat to keep even baby chicks comfortable during the very mild weather of late spring, but not be able to do so in the colder weather of January and February. Yet the first two or three months of the year represent one of the most desir- able periods in which to hatch pullets that will produce well in the fall and winter of the pullet year. At least six pipes one inch in 2 See discussion under Ventilation Without Drafts, page 1. 8 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION diameter will be necessary for cold weather brooding, and fewer than four pipes are inadvisable at any time if the heating system is to. have enough capacity to cope with sudden cold waves. The fire can be checked to lower the temperature of the circulating water but the heat supplied cannot be increased beyond the radiating capacity of the pipes used. TABLE 1. Cost of Brooding Chicks by 10 Day Periods in Units of Two Hundred Fifty. Type of Hover 1st period 2nd period 3rd period 4th period 5th period $1.36 1.12 1.00 .75 .62 .99 .83 .86 .90 .27 1.22 1.54 1.65 1.03 .83 .68 .62 .44 1.49 .78 .46 .39 .06 3.04 2.19 .94 .83 .90 2.52 2.40 1.24 1.756 1.219 .931 .698 .458 .70 .488 .372 .279 .183 Total cost per 100 chicks Hot water (gas heated) Coal oil, blue flame (make 1).. Coal oil, blue flame (make 2).. Coal oil, blue flame (make 3).. Electric (make 1) Electric (make 2) Coal stove, burning coal Coal stove, burning briquettes Average per unit of 250 chicks Average per unit of 100 chicks 1.94 1.54 1.44 1.27 3.16 Data on coal stoves is limited as they were operated only a short time but further data is being taken . Cost calculations were made on basis of coal at $26.00 per ton, carbon briquettes at $22.00 per ton, coal oil at 15 cents per gallon, gas at 90 cents per cubic foot, electricity at 4 cents per K.W.H. The electric hovers were automatically regulated; the other types were manually regulated. Curtains were used with electric and hot water hovers only. In a similar way, success in operating electric brooders is largely influenced by the volume of the pen in which they are used. As shown in Table 1, electric brooder ("Make 1") was operated in a brooder room 8' x 12' x 6' 6" high, with an open front and muslin curtains, at a fuel cost which compared favorably with any other system of heat- ing used. If the pen had been larger (of greater cubical content) and of a more open construction, a larger heating coil would have been necessary to keep the chicks comfortably warm and a greater amount of electricity would have been consumed. Portable, blue flame, coal oil brooder stoves may also prove too limited in heating capacity to give satisfactory results when used for early brooding in large open front laying houses. Such a house is too big and of too open construction, even with all openings closed, for so small a heater to suffice during the colder months. Circular 271] BROODING CHICKS ARTIFICIALLY Coal-burning colony brooder stoves do have enough heat capacity to meet such conditions, but they lack flexibility of heat control and may not be so convenient to operate as oil burners, and moreover, satisfactory fuel is often costly and difficult to obtain in this state. The fire risk, however, is small. A decrease in the size and volume of the pen will decrease the amount of heat required to maintain both the hover and the air of the pen at optimum temperatures and will thereby establish housing con- ditions in which electric and coal-oil heated brooders of limited heating power can be successfully used. The use of auxiliary stoves to take Fig. 5. — Shed roof laying house equipped with a coal brooder stove and used for brooding chicks. When old enough, cockerels can be removed and pullets taught to roost on droppings boards. the chill from the air of the brooding room or pen will serve the same purpose and warm the air of the brooding room to 50° or 60° F., so that electric and coal-oil brooders can be successfully used in the colder months. A brooding house, however, that will successfully care for early as well as late hatches and permit the most economical use of any proved brooding device of reasonable heating power, should have as low a cubical content as effective ventilation and convenience of operation will allow. Economy of Heating. — Table 1 gives very full data on the con- sumption of gas, coal-oil, coal and electricity as sources of heat for brooding purposes. Gas was used in a triple copper coil gas water heater, which heated a hot water pipe system brooder house 75 feet long and 16 feet wide with a 5-foot alleyway and brooding pens 7 feet by 11 feet in size (fig. 6). The coal-oil hovers used were the 42-inch 10 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION size, portable, wickless, blue flame, coal-oil brooder stoves shown in figure 7. The electric brooders were similar to the coal-oil brooders except for the fuel used. Accurate weights were kept of all oil and coal burned and the gas and electricity were measured by meters. Cost data have also been gathered covering the brooding operations of a number of commercial poultry farms. It was found that during February and March, it cost those farms brooding with coal, $3.55 for the fuel to brood 250 chicks, to 50 days of age — the same period and number of chicks used in table 1. The farms using coal-oil paid $3.44, and those using electricity $3.14 for each 250 chick unit during the same period. Reduced to the basis of brooding a unit of 100 chicks to 8 weeks of age, coal was found to cost $1.59 ; coal-oil $1.54 ; and electricity, $1.41. The average cost per 100 chicks for all fuels used was $1.53 for the eight- week period. Dependable Heating System a Necessity. — A heating system for brooding young chicks must be dependable. It must burn throughout the night without material fluctuation and maintain the needed tem- perature under the hovers. Tests by this Station of a number of gravity and pressure feed coal-oil burners in the small coal-burning hot water boiler or furnace of an "overhead" hot water brooding system, have indicated that these burners are not dependable for such work. Anthracite coal has proved more satisfactory in a heater of this type. In much larger boilers used for heating very long brooder houses, electrically driven burners using fuel oil would undoubtedly give dependable service. Such large burners, however, would be of value only on exceptionally large poultry farms. In our tests with the smaller oil burners that are designed more especially for cook stoves, carbon formed at the fuel outlet after five or six hours of burning and clogged it so that the flame slowly became smaller and often blew out. Every effort was made to so regulate the draft as to prevent carbon forming at the fuel outlet but without success. If this should occur at night, not only would the chicks be chilled but the oil would also continue flowing slowly into the hot fire box. If a poultry keeper, upon finding the fire out in the morning and thinking only of his chicks, should try to light the burner before thoroughly airing it and cleaning the ash pit, he would at least risk being badly burned by the explosive ignition of the vaporized oil. The unvaporized oil in the ash pit might also cause a serious conflagration. Tests with portable, blue flame, coal-oil brooder stoves having a visible drip feed of the fuel (sight feed) have shown them unreliable Circular 271] BROODING CHICKS ARTIFICIALLY 11 in maintaining a uniform flame throughout the night. Since the sight feed is located outside of the hover, the number of drops of oil per minute decreases as the brooding room becomes cooler during the night, due to the fact that the viscosity of coal-oil increases as the tempera- ture falls. Consequently the dropping becomes more sluggish. Unless, in cool weather, the drops per minute are increased to produce a maximum flame (top of flame at top of burner) before the attendant Fig. 6. — Triple copper coil gas heater used to heat the water in a hot water brooding system. Can be equipped with automatic gas regulator to hold temperature of hovers at any desired degree of heat. retires, the flame may decrease sufficiently in the night to chill the chicks or even go out and perhaps cause a heavy mortality from the chicks "piling up." Having to operate with so high a flame at night becomes objectionable as the chicks grow larger and stronger, because so much heat is neither necessary nor beneficial, and means a serious waste of fuel. The latest models of these stoves have eliminated the sight feed and use, instead, a very dependable method of flame adjust- ment which is as simple in operation as a central draft oil lamp. 12 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION Simplicity and Durability of Construction, — Simplicity of con- struction in brooding equipment makes for durability and convenience in operation. There are fewer parts to be cared for, to get out of order, and to cause trouble. The burner of the heating system should be simple in design and easy to clean. In the case of electric hovers, the heating coils should be easy of access at least for the emergency repairing of open and short circuits. The use of standard materials, as far as possible, is also very desirable in order that new parts can be readily obtained at local supply houses. The initial installation of dependable materials is the kind of durability insurance that costs the least. Flimsy or inadequate con- struction may lower the initial expense but is costly in the end. Brooding equipment is in constant service twenty-four hours a day during the rearing season and is subject to more or less hard usage. Portable brooders may be subject to considerable moving. The best of materials for each purpose is none too good if maximum efficiency is to be obtained. Ease in Cleaning. — In planning a brooder house, consideration should be given to the ease with which all parts can be cleaned and disinfected, for cleanliness and sanitation are very essential to the continued health and thrifty growth of young stock. It is axiomatic that the harder it is to do a thing, the less often it will be done. A brooder house should be cleaned, scrubbed, hosed out, and disinfected at least once each year. In this work a well drained floor is a great convenience. With a dirt floor a thorough cleaning of this kind cannot be done without converting the floor into a mud hole. Board floors absorb much water, tend to curl in drying, and make an uneven floor surface. Unless a board floor is laid with a slight slope so that it drains well, the water used in cleaning the brooder house must be laboriously shoveled and swept out. A concrete floor costs no more than a well-laid board floor. It has a hard, smooth surface which is easily cleaned and unlike a wood floor, the surface remains smooth and free from shovel-catching irregularities. It is practically ever- lasting and easily laid with a slope so that all water will drain off as fast as it is poured on. The size of the pen in relation to the use of a shovel and broom, ease of removing dirty litter and manure and bringing in clean litter, the use of portable appliances which can be readily gotten out of the way, convenience of arrangement of the hover for cleaning, are all items deserving careful consideration in planning a brooding house requiring a minimum of time and effort to keep clean. Circular 271] brooding chicks artificially 13 Convenience of Operation. — Ease of cleaning the brooder house is but one factor in convenience in caring for chicks. Convenience in inspecting the interior of the hover, regulating the heat and ventila- tion, reading temperatures, feeding and watering are other items that have a direct bearing on the effort required to perform the work. A sink and drain board, for example, in the walkway (fig. 8) of a long house is a great convenience in cleaning buttermilk and water founts. A hover which raises up is much more easily inspected than one which the attendant must get on his hands and knees to peer Fig. 7. — Wickless blue flame coal-oil brooder stove in operation. The can of water placed over the hole in the top of the galvanized iron canopy is used to prevent the wasting of heat through this opening and to increase the humidity of the brooder room. under. The number of gates or doors to be opened in carrying appli- ances, feed, litter, and tools in and out of the pens may greatly reduce efficiency. A house that is elevated above ground so that the attend- ant must constantly carry loads up and down two or three steps or push a wheelbarrow up and down a steep incline can hardly be con- sidered convenient. That construction and arrangement is best which gives the maximum of convenience at the minimum expense. Size of Hover. — The hover should be large enough to accommodate all of the chicks at one time without crowding. On cool nights the room temperature will fall rather low, thereby causing young chicks 14 UNIVERSITY OF CALIFORNIA — EXPERIMENT STATION to remain more closely under the hover than they would on warm nights. Seven square inches of hover space per chick will meet this requirement. A hover 42" in diameter would, on this basis, have a capacity of 200 chicks and one 52" in diameter would comfortably care for 300 chicks. Late in the spring, however, when both the nights and days are much warmer, young chicks will not require so much artificial heat to keep them comfortable. They will not remain so closely under the hover at night, but will spread out, since the heat radiated from the hover will be dissipated and cooled less rapidly by the air of the pen than in cool weather. Under such conditions five or six square inches of hover space per chick may be sufficient. The manufacturer's rating of factory-built brooding equipment should be checked with the data given above to insure the buyer's obtaining sufficient hovers to meet his needs at different seasons. It is much better to have the hover a little large than too small for the number of chicks. Scratching Space Outside the Hover. — Exercise, and fresh air are indispensable to sturdy growth. The more exercise chicks can be induced to take in a cool, well- ventilated pen (fig. 9), the better they will thrive. At the same time they must be provided with a warm hover in which to go when they begin to feel cold. A scratching floor large enough to give the chicks " elbow room" and covered with a good scratching litter, stimulates exercise. It provides ample space away from the warm and more enervating atmosphere of the hover where chicks can run and scratch, fill their lungs with fresh cool air, quicken and strengthen digestion, become used to normal temperatures, and make strong, rapid growth. Toe-picking is a pernicious habit undoubtedly induced, at first, by curiosity concerning the moving toes of other chicks. Chicks have a natural taste for animal products and once they draw blood, they seem to persist in the practice and transmit it to others. Chicks seriously toe-picked apparently suffer a severe nervous shock which is fatal in a majority of cases. The most effective measures to take against toe-picking are prevention and the immediate removal of toe-picked chicks to a separate pen or pens. The practice of toe-picking is fostered (1) by crowding chicks (instead of giving them roomy quarters) and (2) by over-feeding. Small pens keep chicks so close together that their attention is apt to become focused on each other's toes. Keeping chicks slightly hungry and busy in pens and yards large enough to keep them inter- ested in other directions represents the ounce of prevention that is Circular 271] BROODING CHICKS ARTIFICIALLY 15 worth a pound of cure. Do hen-reared chicks toe-pick? Are they crowded in large numbers into small pens and pocket handkerchief runs? A brooder pen with a total floor area, including the hover, of one-half square foot per chick is not too large for chicks less than five weeks of age. The area per chick should then be increased to allow for the increase in growth. This is usually done by removing the cockerels to separate pens since a normal hatch contains approxi- mately one-half females and one-half males. Ample room for further growth is thus provided. muslin curtain Fig. 8. — Open front walkway brooder house in which any kind of hover may be used as indicated. Pens can be thrown together by raising boards A if it is desired to use one room for the hover and one as a cool room. Size of the Pen. — The number of chicks to be brooded in each pen has a direct bearing on the size of the pen. If one-half square foot of floor space per chick is allowed, 100 chicks would require a pen containing 50 square feet; and 200 chicks a pen containing 100 square feet of floor space. A brooder pen 16 feet deep, for example, would need to be only 3% feet wide for 100 chicks — (too narrow a width for convenience), 6*4 feet wide for 200 chicks, and so on. This Station has found that as the size of the flock brooded together is increased, other things being equal, the mortality tends to increase. Strong chicks will always crowd the weaker ones away from the feed, trample on them, pick at them and otherwise manifest their superior strength. Increasing the number of chicks kept together 16 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION emphasizes this condition. The "law of the survival of the fittest" operates with increasing effect as the number of chicks competing with each other in one flock is multiplied. . The investment and labor cost per chick is reduced, it is true, as the size of the flock is increased, but what is gained if the vigor of the flock is impaired, rate of growth checked, death loss raised, and a greater number of runts and culls produced? Extended analysis of the decrease in cost of labor, investment, and so on obtained by enlarg- ing the size of flocks of chicks brooded together, as compared with the decrease in returns resulting from increased mortality, greater num- ber of culls, etc., has shown that approximately 200 chicks is the most economical number that can be reared in one flock. The most important factor for success in rearing chicks in any size of flock, however, is the skill and attention of the person caring for them. Some poultry keepers are successful in rearing chicks in rather large flocks while others with less natural ability, skill, and experience are unsuccessful in small units. It is a well recognized fact that as the size of the flock brooded is enlarged, greater atten- tion and skill are required to prevent increasingly poor results in both quality and quantity. ■ System of Yarding. — The size and the "range quality" of the yards exert, perhaps, a more positive influence on the strong growth of young stock after they are a few weeks old (confined stock excepted) than the size of the pens within the brooding house, because the birds will spend most of their time out of doors if conditions are at all favorable. "Range quality" refers to the available supply of natural shade and green pasturage and to the condition of the soil which, in the case of yards that are bare all or a part of the time, should be kept loose and well pulverized by frequent cultivation. The most successful way to rear poultry, so far as sturdy, rapid growth is concerned, is under conditions of free range where the growing fowls have freedom of action, gain exercise in ranging widely over the fields, and pick up a variety of food. '.~ Succulent, green pasturage, whether on free range or in large yards; will stimulate a more vigorous growth in young stock in hot weather than bare- range or yards even though an abundant • amount of tender green stuff is cut and fed daily in green feed hoppers. ' To grow green crops such as alfalfa and Sudan grass for poultry pasturage purposes in most sections of California, however, irrigation is required. To prevent the fowls from seriously injuring such pasturage by too close cropping of the tender growth, not more than 300 birds half grown or larger can safely be run per acre. Circular 271] brooding chicks artificially 17 A double yard system with large yards which can be irrigated in summer, most closely approaches free range conditions in the results obtained. With large double yards attached to each brooder pen, one yard can be plowed and planted to some quick growing crop, such as barley in the cooler months and Sudan grass in summer, while the chickens run in the other. When the green crop has attained a height of about eight inches, the chickens are turned in on it and the other yard is then irrigated, plowed, and sowed. Cropping supplies young, succulent pasturage for the fowls; the manure Fig. 9. — Showing further details of the arrangement and construction of the front windows and muslin curtain frame illustrated in Fig. 8. The curtain is hinged at the top and folds up. This is an excellent front arrangement for any kind of brooder house. deposited over the yards instead of being left as a medium for the propagation and spread of internal parasites and disease germs, is utilized as fertilizer ; and the frequent cultivation keeps the soil loose and pulverized, thoroughly aerated, and in condition to be acted upon by the sun 's rays. Dry air and sunlight are powerful germicides and disease-preventing agencies. The loose, moist soil stimulates quick, tender growth of health-promoting greenstuff and provides favorable conditions for dusting. In figure 10 is illustrated a free range system of rearing chicks which works splendidly where large fields or orchards are available. 18 UNIVERSITY OF CALIFORNIA — EXPERIMENT STATION The houses shown are 8 feet by 8 feet in size and of knock-down con- struction. They can be knocked down by two men in twenty minutes, loaded on a wagon, hauled to a new location and set up again in another twenty minutes. Houses of this type may be built on 4 inch by 6 inch runners and without a floor. Then instead of cleaning out the night droppings at intervals, each house may be hauled a short distance to a clean site. The houses can be set up near the dwelling in spring and used for brooding. Each house will hold a maximum of 200 chicks. Coal-oil or electric hovers can be used. When the chicks no longer require arti- ficial heat, the sexes should be separated and the cockerels put in quarters where they can be grown and finished for market. The houses with the pullets can then be placed along the edge of an alfalfa field or orchard. If the cockerels are put on range too, they should be widely separated from the pullets. Only one house at a time should be moved out on the range and the pullets should be kept confined for two days before they are allowed to run at large. If they are not confined at first, they will all return to the place from which the house was moved and the poultry keeper will have the exasperating task of catching them at night and putting them back in their house. As soon as the first lot of young pullets moved has been running out for two or three days and all go to roost nicely each night, a second house of pullets may be moved out, but it should be placed at least fifty feet from the first one. This second lot of pullets should be kept confined two days. Then the birds in the first house should be confined for the first two days that the second lot is let out. Other- wise, the two lots will mix and perhaps all or nearly all will use the same house. The practice described here will teach each lot of pullets to roost in its own house. As each new house is brought out, the birds should be confined for two days and then the other groups of birds on that range kept confined for two days while the new lot learns to run out and return to its own house. If the houses are located, for example, between a grain stubble field and a field of alfalfa and close to an orchard, the birds will have ideal conditions. They can range the stubble and alfalfa fields night and morning for grain, insects and green herbage and work in the shade of the trees in the hot part of the day. The pullets will make a rapid, hardy growth and pick up most of their living, requiring only protection from predatory birds and animals and plenty of fresh water. Circular 271] BROODING CHICKS ARTIFICIALLY 19 This system of rearing chickens requires no fencing which would interfere with plowing and irrigating, in orchards or cropped fields, and is, therefore, very convenient for use on the farm or in connec- tion with orchards. It has the further advantage of giving the fowls free range and enabling them to pick up a large part of their feed in the fields. In some locations the birds may be exposed to greater danger from hawks, weasels, and other enemies than would be the case if they were yarded, but as a rule, the most profitable way to rear Fig. 10. — Colony rearing houses on free range. A large alfalfa field is at the rear of the line of houses. chickens is under good, free range conditions. Laying hens can also be kept in this way. If the movable houses are to be used for brood- ing young chicks or for laying hens in winter however, they should have floors to make them more sanitary and convenient to clean for they cannot be moved as frequently in winter as in summer. Summer Shade. — Good shade should be provided in the brooder yards in summer to induce the chicks to spend as much time out of doors as possible. Abundant exercise in the fresh, pure, outdoor air promotes sturdy growth, the chicks become more quickly accustomed to cooler temperatures and the heat of the hover can accordingly be reduced more rapidly. Natural shade is more desirable than arti- ficial shade. Trees are excellent because they give a dense, wide- 20 UNIVERSITY OF CALIFORNIA — EXPERIMENT STATION spreading shade without restricting the free circulation of air. For narrow nursery brooder yards, vines trained over the tops of the yards serve very well. The weeping mulberry headed high and trained over the tops of narrow yards also provides good shade. FEEDING YOUNG CHICKS First Care of Chicks. — The interior of the brooder pen, as well as all equipment and utensils, should be thoroughly washed, scrubbed, and disinfected a few days in advance. When thoroughly dry, the floor around the hover should be lightly covered with sifted light or dark sand and the hover temperature regulated to between 90° and 95° F., with the thermometer near the outer edge of the hover and the center of the thermometer bulk two inches above the floor. Eight- inch boards or one-inch mesh wire netting one foot wide should be used to form a small enclosure around the hover for the first three or four days to prevent the chicks from getting too far away until they learn to use it. In cool weather the wire netting ring should be faced with burlap sacks cut open and sewed to the wire. In large brooder pens, the enclosure may be enlarged a little each day in order to gradually accustom the chicks to the larger area. In small pens this is not necessary. About twenty-four hours after the hatch is completed, the chicks should be taken from the incubator, placed under the hover in the brooder pen, and given fresh water to drink. It is better to move them into the brooder in the morning so that they can be closely watched for the first five or six hours. No solid food should be given until the chicks are from sixty to seventy-two hours old. At hatching, a good deal of yolk material still remains undigested in the chick's abdomen and should be absorbed before the digestive organs are required to handle other food. If the common type of chick fountain having a round pan and holding from one and one-half to two quarts of water is used, one such fountain should be provided for each 100 chicks. Fountains with conical tops are better than those with flat tops because the chicks cannot perch on them and foul the fountain and water with droppings. Fountains should be washed at least once a day and the water changed twice a day. Chicks should be allowed in the yards as soon as possible. Contact with the ground and exercise out of doors will be found to promote a more rapid and hardy growth. Just how soon after being put in the brooder they should be allowed in the yards will depend entirely on weather conditions. The cooler the weather, the older and stronger CIRCULAR 271] BROODING CHICKS ARTIFICIALLY 21 they must be to withstand the outdoor air without becoming chilled. In winter it may not be safe to allow them in the yards until they are four or five weeks old and then only during the warm part of the day, at first. In May they can perhaps be out of doors during the middle of the day when three or four days old. They should be kept indoors in rainy weather at any time of the year. Feeding Milk. — If it can be obtained at a reasonable cost, butter- milk or sour skimmilk may be given to chicks from the time they are removed to the brooder. Sour skimmilk will be consumed more evenly if the curd is broken into fine particles by vigorous agitation with a dasher before being fed. Milk may be given in the morning and water in the afternoon, or both may be made available during the whole day. If mash is kept before young chicks, however, milk should not be fed after 3 p.m. Chicks having access to both mash and milk in the late afternoon are prone to over-eat of these foods before going to bed. Digestion is slower at night than during the day when the chicks are vigorously exercising, and a mushy mixture of these foods in the hot interior of the crop at this time may ferment before it can be digested. The result is a condition of colic or sour crop which is generally fatal to chicks under three weeks of age and weakening to older chicks. Young stock which are fed all the buttermilk or sour skimmilk they will drink need no other animal food such as meatscrap, fish- scrap, or bonemeal in their diet. If only a small amount of milk can be fed, however, animal feed should not be eliminated from the ration but merely reduced in quantity. One pound of commercial meatscrap or fishscrap should be considered equal to fifteen pounds of fresh buttermilk. If chicks are physicked from drinking too eagerly or if they develop sour crop, the milk should be fed in the morning only. Some lots of chicks may develop an abnormal appetite for milk ; this should be curbed by feeding more sparingly. Milk should be fed in crocks or enameled pans. The lactic acid corrodes galvanized iron pans. Milk Treatment for Coccidiosis. — The feeding of fresh buttermilk or sour skimmilk is the most effective treatment which has yet been used for the control of coccidiosis 3 in growing chicks. Coccidiosis is an infectious disease caused by a protozoan organism which invades the caeca and intestinal tract in young stock. Among the most prominent symptoms are a rapid loss of vitality throughout the flock, huddling together in corners and under the hover with every 3 For a more detailed discussion of coccidiosis, the reader is referred to Circular No. 251, California Agricultural Experiment Station. 22 UNIVERSITY OF CALIFORNIA — EXPERIMENT STATION appearance of being cold, the passing of bloody droppings, and a sud- den increase in mortality. Bloody droppings are usually evident only in acute outbreaks. This disease might be termed a young stock disease because it rarely occurs in chicks less than two or more than sixteen weeks of age. A post-mortem examination of dead chicks usually shows enlarged caeca whose contents are pasty or semi-liquid and brown, reddish brown, or bloody. The outer walls of the caeca may show flecks of red indicating inflamed areas. Frequently this inflammation extends into the intestines. As soon as the disease is discovered, the feeding of mash and water should be stopped and the birds given only a scanty feeding of grain morning and night. Crocks of buttermilk or sour skimmilk should now be kept constantly before the chicks. Green feed is fed as usual. Taking away all drinking water induces a heavy consumption of milk which acts as a strong laxative and causes the chicks to pass large amounts of very watery excreta. As a result, the floor of the brooder pen becomes very damp and must be cleaned daily and re-strawed with just enough litter to absorb the moisture. Daily cleaning is also valuable in checking coccidiosis, since this disease is spread by the infected droppings of diseased birds. Cleaning out the soiled litter removes the infected excreta before it can do any serious harm in intensifying the ravages of the disease. Since buttermilk has considerable food value, the treatment not only checks the disease rapidly but the chicks may make a considerable gain in weight by the end of the treatment. The treatment should be continued for about ten days or until all signs of the disease have disappeared. Then the feeder can begin to slowly bring the chicks back to the normal method of feeding. The feeding of milk alone may now be limited to the morning period for two or three weeks and both milk and water given in the afternoon. In resuming the feeding of mash, it should be fed for only one hour at noon for the first three days and the mash feeding period then lengthened one hour every three days until it is being fed normally. The usual method of feeding grain may be resumed in like manner. Feeding Grain. — When from 60 to 72 hours old, chicks are fed a chick grain mixture on a board or in a shallow chick hopper (fig. 11) placed just outside of the hover. The following mixture is recom- mended : 33%% cracked wheat (by weight). 33%% fine cracked corn. 33%% steel-cut oats. Circular 271] BROODING CHICKS ARTIFICIALLY 28 The grain mixture should be left before the chicks till they learn to eat readily. This will require one or two days because at first they will pick considerably but swallow little. On the second day the grain hoppers can usually be removed at noon and a small amount of grain then sprinkled over the sand just outside the hover. If this grain is eaten readily, more should be given at four in the afternoon and again the next morning, feeding each time only what will be cleaned up in about an hour. The chicks should be sufficiently strong and active by this time that they can be fed grain in a scratching litter. This litter may consist of fine-cut alfalfa hay spread lightly over the scratching floor. The grain should be scattered in the litter three times a day till the feeding of mash is begun, when the noon feeding of grain should be omitted. When the birds are about four or five weeks of age, a mixture of one-half cut alfalfa hay and one- half cut straw may be used in place of the straight alfalfa litter, and a few weeks later whole straw, if not too coarse, can be used. Planer shavings are also used as a litter material, but are likely to pack too much and do not conceal the grain. Moreover they draw dampness in wet weather. Fig. 11. — Chick mash hopper. A hopper 34% inches long, 5 inches wide, and iy 2 inches high, inside dimensions, is a very convenient size. The %-inch mesh hardware cloth grid prevents the chicks from wasting feed by scratching it out of the hopper. The depth of the scratching litter should be increased as the chicks grow older, out care must be taken not to get it so deep as to prevent their digging to the bottom of it easily, nor so shallow as to permit the chicks to get the grain without effort. The scratching litter, if used wisely, is an effective means of supplying brooder chicks with healthful exercise. Exercise aids in developing sturdy chicks that make rapid growth and is one of the most valuable preventives of disease. Approximately one-half pint of grain should be given at a feeding to each one hundred chicks under one week of age. This amount may be increased from week to week as the birds grow larger. If grain is found in the litter at feeding time, the amount given at a feeding should be reduced. If all the grain has been scratched out of the litter and the chicks act exceptionally hungry at meal time, the 24 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION amount of grain should be increased. They should be fed only enough grain to keep them growing thriftily and their appetites keen. They should come to each meal reasonably hungry. Changing from Chick to Growing Grains. — If steel-cut oats are too costly to be used, cracked hulled barley, cracked Milo or cracked Egyptian corn can be substituted. However, no better grain than hulled oats can be used as a starting feed for the first few weeks of a chick's life, After this period other grains may be used to replace the oats. Steel-cut oats are preferable to rolled oatmeal, or so-called breakfast rolled oats, because the latter are likely to become sticky when moistened by the juices in the crop and ' ' ball up ' ' into a cohesive mass, difficult to digest, especially when fed alone. Cracked grains should be replaced by whole grains, in the case of small grains like wheat, milo, oats and barley, at six weeks of age when the chicks are large enough to eat them. Fine cracked corn should not be replaced by the coarse cracked grade, however, until two or more weeks later. Whole barley may be added to the grain ration when the chicks are from ten to twelve weeks old. It should be used moderately at first and gradually increased, but the total amount used should not exceed fifty per cent of the grain ration. One should not be too hasty in changing from fine to coarser cracked and whole grains. This is particularly true with yellow corn because different lots of the coarse cracked grade may vary consid- erably in coarseness. The larger particles of a very coarse lot might prove injurious. A little care in this matter is well worth while. Feeding Mash. — When chicks are seven days old, the feeding of a dry mash is usually beg'un. The following formula and method of feeding are recommended : 25% bran. 25% shorts. 20% yellow corn meal. 10% soybean meal. 15% meatscrap. .5% very finely ground bonemeal. 2|% granulated chick charcoal. '■■ Note.— -All' proportions are by weight. The charcoal is fed in addition to the 100% mixture of feed stuffs. At 7 days old begin feeding dry mash from 10 a.m. to 11 a.m. At 14 days old begin feeding dry mash from 10 a.m. to 12 m. At 28 days old begin feeding dry mash from 10 a.m. to 1 p.m. At 42 days old begin feeding dry mash from 10 a.m. to 2 p.m. Cieculas 271 BROODING CHICKS ARTIFICIALLY 25 For pullets and cockerels that are to be raised for laying and breeding, a well formulated laying mash should replace the chick or growing mash at three months of age. The chick mash is a high- protein feed designed to produce strong, rapid growth. After three months of age, however, a mash of lower protein content, such as a laying mash, is better suited to the development of vigorous, go-od- sized pullets. The hoppers of laying mash should be closed two hours before the evening feeding of grain and opened at the morning feeding of grain. 4 / mesh netting Fig. 12. — Green feed hopper for chickens over three weeks old. Green Feed. — Fresh, tender green feed such as lettuce, chard, clover lawn clippings, rape, kale, beet tops, young green barley, young alfalfa and Sudan grass should be fed plentifully to growing chicks after they are a few days old. Materials like Sudan grass and alfalfa will be eaten better by the chicks if cut very fine with a cutter. It is much more beneficial to chickens of any age to allow them to range over areas of growing green crops than it is to feed them cut green stuff. But if greens must be cut and fed by hand, the use of a green feed hopper (fig. 12), in which to feed such finely cut green stuff as alfalfa will greatly lessen waste. Such a hopper holds the fresh material together so that it remains succulent and unwilted for a much longer time than it would if it were fed on the ground and scattered about by the chickens. Enough green stuff should be put in the rack after the morning feeding of grain to last till noon, and only as much more added at 4 For a more detailed discussion of feeding, the reader is referred to Circular No. 242, California Agricultural Experiment Station, entitled ' ' Poultry Feeding. ' ' 26 UNIVERSITY OF CALIFORNIA — EXPERIMENT STATION noon as will be cleaned up before night. Leafy green feeds, like lettuce and kale, can be thrown to the chicks without cutting. They will get considerable exercise in pulling the leaves to pieces. CROWDING Crowding is a prevalent cause of high mortality in chicks. Fre- quently more chicks are put in a brooder pen than it will satisfac- torily accommodate at the start and then no provision is made to relieve this congestion at the earliest possible moment. It is appar- ently overlooked, or, perhaps, not fully realized, that a Leghorn chick will double its weight in three weeks and triple it in five weeks. With so rapid an increase in size, a pen of even normal dimensions for a certain number of day-old chicks is quickly outgrown. In a pen over- crowded to start with, the congestion is quickly intensified and a heavy mortality results. One-half square foot of floor space per chick should be allowed in the brooder room and seven square inches per chick under the hover. The very detrimental effect of crowding on growing chicks should not be overlooked by the poultry keeper and provision should be made to give the chicks more room as they increase in size. Ample room will pay in lessened mortality, less cull stock, and more rapid growth ; cockerels will reach broiler weight more quickly and pullets will attain normal growth and lay at an earlier age. In this connection the reader's attention is called to the discussion of yarding on page 16. SEPARATION OF SEXES One way to give growing chicks more room to develop is to separate the cockerels and the pullets just as soon as the sexes can be dis- tinguished. In the case of such breeds as the Leghorn, this can usually be done at about four weeks of age; with the heavier breeds it is often very difficult to identify the sexes until the birds are half grown. The cockerels, of the light breeds, particularly, begin very early to demonstrate their greater strength by crowding the pullets away from the feed troughs, picking at them, and otherwise annoying them. The early separation of the sexes will allow the pullets to develop much more rapidly, and the cockerels can be fed and cared for to better advantage in developing them for market or breeding purposes. CHICKS PILING UP Brooder chicks that have not yet learned to roost always crowd together when they become chilly. It is instinctive for them to try to get underneath something warm, as they would under the mother Circular 271] BROODING CHICKS ARTIFICIALLY 27 hen, and so they attempt to get under each other as they crowd together. The strongest chicks are able to push the weakest aside and to work their way to the bottom of the huddled group. Here they are soon smothered to death and flattened out by the compact mass of chicks on top of them. The larger and more numerous the chicks in any given lot, the more serious are the results from crowding and piling. Fig. 13. — Roosts permanently installed in brooder pen so that chicks may learn to roost naturally without the use of " forcing' ' methods. Piling may result from (1) the hover temperature dropping at night, (2) a rapid loss of vitality from coccidiosis, (3) keeping the hovers and pens so hot that the chicks, being accustomed to high tem- peratures (hot house chicks) are quickly chilled by sudden changes in the weather or accidents to the brooding system, and (4) trans- ferring the chicks from warm to cold brooders in too large lots before thev have learned to roost well. TEACHING CHICKS TO ROOST It is very desirable to have chicks learn to roost at an early age. The roosts (1) keep the chicks separated and prevent their bunching together as they do after two weeks of age when sleeping on the floor of the brooder pen, (2) raise the chicks above the floor so that the air can circulate freely under and around them, (3) supply better 28 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION ventilation, and (4) eliminate the danger of chicks piling up, for they cannot pile up when roosting without falling off. The more quickly chicks are accustomed to do without artificial heat, the stronger will be their growth and the sooner they will learn to roost. Perhaps the most satisfactory way to induce chicks to roost is to place roosts in the brooder room and let them learn to roost naturally. Applications of this method are illustrated in figures 2 and 13. When young stock are rather slow in learning to roost and it becomes necessary to move them out of the brooder house, they can be safely transferred to a number of growing houses in lots of twenty- five. Twenty -five is too small a number to cause any loss from piling up, and removing slow roosting chicks to strange quarters is one of the quickest ways to induce them to roost. The first twenty-five chicks put in each pen are kept confined until they are all accustomed to their new quarters and to roosting. This will take two or three days. Then twenty-five more can be added to each pen. The first ones quickly teach the newcomers to roost, so that twenty-five more may be added every two or three days until the full quota has been put in each pen. The safest guide in adding each lot of twenty-five is not to add more until those previously put in are roosting nicely. If the roosts are on a droppings board and not near the floor, a wire covered panel should be placed vertically from floor to front edge of droppings board to keep chicks from going underneath. An inclined portable runway, one foot wide and with cross cleats four inches apart, should also extend from the floor to the droppings board to enable the birds to get up on the roosts without difficulty. These devices will greatly facilitate teaching the chicks to roost. Another method sometimes used is known as "forced roosting." The droppings board of a laying house is prepared by stretching one- or two-inch mesh wire netting on the under sides of the roosts and placing a light panel covered with this netting in front of the roosts so as to fill the opening from droppings board to ceiling. This front panel should have a netting-covered door in it through which the chicks and troughs of feed can be put into the enclosure. When completed a tight coop with wire netting bottom and front is formed. As soon as the chicks have learned to do without artificial heat and are large enough to roost, they are taken from the brooder room and put into the previously prepared enclosures described in the pre- ceding paragraph. Since wire netting is stretched tightly under the roosts, the chicks must either perch on the roosts or on the wire netting stretched tightly between them. Should they crowd together and Circular 271] brooding chicks artificially 29 attempt to pile up, the roosts and wire interfere with their getting together and resting comfortably. The circulation of air through the wire from below also keeps the bottom of the attempted "pile up" of chicks as cool as the top and the bottom chicks get just as much fresh air as any of the others. Crowding and piling up are there- fore quickly discouraged and the chicks soon learn that the roosts are much more comfortable than wire netting to roost on. Forced roosting should not be attempted with chicks under six weeks of age or with lots of more than 200 in any one enclosure. It is also best to separate the sexes when using this method, since cockerels and pullets learn to roost more readily when placed in separate coops. The authors wish to acknowledge their indebtedness to Professor W. E. Lloyd of the Division of Poultry Husbandry for the experi- mental data on which Table 1 is based ; to Mr. R. B. Easson, Extension Poultry Specialist, who was instrumental in making the field survey from which was obtained other fuel costs of brooding given in the test ; and to Mr. J. D. Long of the Division of Agricultural Engineer- ing for his help in lettering the drawings. Blueprint plans for the houses illustrated in figures 1, 5, and 8 of this bulletin may be obtained on loan from the Division of Agricultural Extension. College of Agriculture, Berkeley, California. STATION PUBLICATIONS AVAILABLE FOB FREE DISTRIBUTION No. 253. 261. 262. 263. 268. 270. 273. 275. 276. 277. 278. 279. 280. 283. 285. 286. 287. 294. 298. 804. 308. 312. 317. 319. 321. 324. 325. 328. 331. 334. BULLETINS No. Irrigation and Soil Conditions in the 335. Sierra Nevada Foothills, California. Mel ax u ma of the Walnut, "Juglans 336. regia." Citrus Diseases of Florida and Cuba 339. Compared with those of California. Size Grades for Ripe Olives. 341. Growing and Grafting Olive Seedlings. 343. A Comparison of Annual Cropping, Bi- 344. ennial Cropping and Green Manures on the Yield of Wheat. 347. Preliminary Report on Kearney Vine- yard Experimental Drain. 348. The Cultivation of Belladonna in Cali- 349. fornia. The Pomegranate. 350. Sudan Grass. 351. Grain Sorghums. 352. Irrigation of Rice in California. Irrigation of Alfalfa in the Sacramento 353. Valley. 354. The Olive Insects of California. 355. The Milk Goat in California. 357. Commercial Fertilizers. Vinegar from Waste Fruits. Bean Culture in California. 358. Seedless Raisin Grapes. A Study of the Effects of Freezes on 359. Citrus in California. 360. I. Fumigation with Liquid Hydrocyanic Acid. II. Physical and Chemical Prop- 361. erties of Liquid Hydrocyanic Acid. Mariout Barley. 362. Selections of Stocks in Citrus Propa- 363. gation. Caprifigs and Caprification. 364. Commercial Production of Grape Syrup. Storage of Perishable Fruit at Freezing 365. Temperatures. 366. Rice Irrigation Measurements and Ex- periments in Sacramento Valley, 368 1914-1919. Prune Growing in California. 369. Phylloxera-Resistant Stocks. Preliminary Volume Tables for Second- Growth Redwood. Cocoanut Meal as a Feed for Dairy Cows and Other Livestock. The Preparation of Nicotine Dust as an Insecticide. The Relative Cost of Making Logs from Small and Large Timber. Studies on Irrigation of Citrus Groves. Cheese Pests and Their Control. Cold Storage as an Aid to the Market ing of Plums. The Control of Red Spiders in Decidu- ous Orchards. Pruning Young Olive Trees. A Study of Sidedraft and Tractor Hitches. Agriculture in Cut-over Redwood Lands. California State Dairy Cow Competition. Further Experiments in Plum Pollina- tion. Bovine Infectious Abortion. Results of Rice Experiments in 1922. The Peach Twig Borer. A Self-mixing Dusting Machine for Applying Dry Insecticides and Fungicides. Black Measles, Water Berries, and Related Vine Troubles. Fruit Beverage Investigations. Gum Diseases of Citrus Trees in Cali- fornia. Preliminary Yield Tables for Second Growth Redwood. Dust and the Tractor Engine. The Pruning of Citrus Trees in Cali- fornia. Fungicidal Dusts for the Control of Bunt. Avocado Culture in California. Turkish Tobacco Culture, Curing and Marketing. Bacterial Decomposition of Olives dur- ing Pickling. Comparison of Woods for Butter Boxes CIRCULARS No. No. 70. Observations on the Status of Corn 161. Growing in California. 164. 87. Alfalfa. 165. 111. The Use of Lime and Gypsum on Cali- fornia Soils. 166. 113. Correspondence Courses in Agriculture. 167. 117. The Selection and Cost of a Small 170. Pumping Plant. 136. Melilotua mdica as a Green-Manure 172. Crop for California. 173. 127. House Fumigation. 129. The Control of Citrus Insects. 174. 144. Qidium or Powdery Mildew of the Vine. 175. 151. Feeding and Management of Hogs. 152. Some Observations on the Bulk Hand- 178. ling of Grain in California. 179. 153. Announcement of the California State Dairy Cow Competition, 1916-18. 182. 154. Irrigation Practice in Growing Small Fruit in California. 184. 155. Bovine Tuberculosis. 188. 157. Control of the Pear Scab. 190. 159. Agriculture in the Imperial Valley. 193. 160. Lettuce Growing in California. 198. Potatoes in California. Small Fruit Culture in California. Fundamentals of Sugar Beet Culture under California Conditions. The County Farm Bureau. Feeding Stuffs of Minor Importance. Fertilizing California Soils for the 1918 Crop. Wheat Culture. The Construction of the Wood-Hoop Silo. Farm Drainage Methods. Progress Report on the Marketing and Distribution of Milk. The Packing of Apples in California. Factors of Importance in Producing Milk of Low Bacterial Count. Extending the Area of Irrigated Wheat in California for 1918. A Flock of Sheep on the Farm. Lambing Sheds. Agriculture Clubs in California. A Study of Farm Labor in California. Syrup from Sweet Sorghum. CIRCULARS — Continued No. 199. 201. 202. 203. 205. 206. 208. 209. 210. 212. 214. 215. 217. 218. 219. 224. 228. 230. 232. 233. 234. 235. 236. 237. 238. 239. 240. Onion Growing in California. Helpful Hints to Hog Raisers. County Organizations for Rural Fire Control. Peat as a Manure Substitute. Blackleg. Jack Cheese. Summary of the Annual Reports of the Farm Advisors of California. The Function of the Farm Bureau. Suggestions to the Settler in California. Salvaging Rain-Damaged Prunes. Seed Treatment for the Prevention of Cereal Smuts. Feeding Dairy Cows in California. Methods for Marketing Vegetables in California. Advanced Registry Testing of Dairy Cows. The Present Status of Alkali. Control of the Brown Apricot Scale and the Italian Pear Scale on Decid- uous Fruit Trees. Vineyard Irrigation in Arid Climates. Testing Milk, Cream, and Skim Milk for Butterfat. Harvesting and Handling California Cherries for Eastern Shipment. Artificial Incubation. Winter Injury to Young Walnut Trees during 1921-22. Soil Analysis and Soil and Plant Inter- relations. The Common Hawks and Owls of Cali- fornia from the Standpoint of the Rancher. Directions for the Tanning and Dress- ing of Furs. The Apricot in California. Harvesting and Handling Apricots and Plums for Eastern Shipment. Harvesting and Handling Pears for Eastern Shipment. No. 241. 242. 243. 244. 245. 247. 248. 249. 250. 251. 252. 253. 254. 255. 256. 257. 258. 259. 260. 261. 262. 263. 264. 265. 266. Harvesting and Handling Peaches for Eastern Shipment. Poultry Feeding. Marmalade Juice and Jelly Juice from Citrus Fruits. Central Wire Bracing for Fruit Trees. Vine Pruning Systems. Colonization and Rural Development. Some Common Errors in Vine Prunimg and Their Remedies. Replacing Missing Vines. Measurement of Irrigation Water on the Farm. Recommendations Concerning the Com- mon Diseases and Parasites of Poultry in California. Supports for Vines. Vineyard Plans. The Use of Artificial Light to Increase Winter Egg Production. Leguminous Plants as Organic Fertil- izer in California Agriculture. The Control of Wild Morning Glory. The Small-Seeded Horse Bean. Thinning Deciduous Fruits. Pear By-prodncts. A Selected List of References Relating to Irrigation in California. Sewing Grain Sacks. Cabbage Growing in California. Tomato Production in California. Preliminary Essentials to Bovine Tuber- culosis Control. Plant Disease and Pest Control. Analyzing the Citrus Orchard by Means of Simple Tree Records. The Tendency of Tractors to Rise in Front; Causes and Remedies.