UNIVERSITY OF CALIFORNIA COLLEGE OF AGRICULTURE AGRICULTURAL EXPERIMENT STATION CIRCULAR No. 251 August, 1922 RECOMMENDATIONS CONCERNING THE COMMON DISEASES AND PARASITES OF POULTRY IN CALIFORNIA By J. R. BEACH and S. B. FREEBORN University of California, Avian Pathology Laboratory, Petaluma, California. Z UNIVERSITY OF CALIFORNIA EXPERIMENT STATION CONTENTS page Introduction 2 General preventive measures 2 Chicken-pox and canker or avian diptheria 5 Colds and roup 13 Nutritional disease resembling roup 15 Fowl cholera associated with ruptured egg yolk 19 Tuberculosis 20 Coccidiosis 22 White diarrhoea of chicks 25 Leg weakness of chicks 27 Blackhead in turkeys 27 Common diseases of birds 30 Lice 31 Mites 33 Ticks 37 Fleas 38 Flies 39 Tapeworms 40 Roundworms 42 Cecum worms 44 INTRODUCTION There are a number of diseases and parasites which may attack poultry and cause severe loss. The modern practice of raising large numbers of fowls continuously on relatively small areas has increased the liability of their occurrence. It is obvious, therefore, that some knowledge of the means of recognizing, preventing, and controlling the more common diseases and parasites is of great importance to all poultry raisers. GENERAL PREVENTIVE MEASURES The most effective means of combating diseases and parasites of all species of animals is to prevent their occurrence. This principle is especially applicable to poultry because fowls are commonly kept in such large flocks that disease may spread very rapidly, and cause con- siderable loss before it is recognized. Furthermore, the value of a single fowl is so small that it is impractical to administer individual treatment to many sick ones. Disease is very often introduced by new stock. This is more apt to occur with grown birds than with chicks. It is safest, therefore, for a beginner to buy hatching eggs or day-old chicks. Adult "birds which are added to existing flocks should be kept separate for at least two weeks before they arc put with the others. Even with this pre- caution the presence of some infectious diseases, such as tuberculosis, may be overlooked. Feeding methods are responsible for the sickness and death of birds in many flocks. Frequently losses from this cause are so numer- Circular 251] POULTRY DISEASES AND PARASITES 3 ous as to resemble the effect of an infectious disease. It is quite appar- ent, therefore, that proper feeding of fowls is an important factor in disease prevention. The soil of yards in which diseased fowls or those infested with intestinal parasites are kept soon becomes contaminated with disease germs or parasite eggs. By this means disease and parasites may be spread to other fowls placed in the same yards. Parasite eggs may remain alive for years, but most disease germs which affect fowls will die in a few months if the yards are not used. The danger of infection from this source will be greatly reduced if fowls are kept but a few months at a time in the same yards. The "double-yard system" which provides two yards for each house should be adopted. This will permit fowls to be kept in one yard while the other is being plowed and cropped. It is also desirable that the soil be of a light sandy type and well drained, rather than of a heavy type or poorly drained. Water holes in the yards especially are to be avoided. The type of poultry house may have considerable bearing on the occurrence of disease. Sunlight is one of the most effective germ destroyers. Houses should therefore be so constructed and located that the direct rays of the sun will reach all parts some time during each day. Other essential points are to provide good ventilation with- out draftiness, to make provision for keeping out rain during stormy weather, and to provide drainage away from the house so that the floors will not become damp. It is also desirable to have the house so arranged that all parts can be easily cleaned and to have all nest boxes, feed troughs, etc., removable. The symptoms caused by some different diseases are so similar that it is not always possible, by symptoms alone, to differentiate between an infectious and a non-infectious one. Therefore, any sick fowls should be regarded with suspicion and be removed from the flock as soon as discovered. Strict adherence to this practice will assist in preventing serious outbreaks of infectious diseases. A sick fowl either should be isolated in comfortable quarters and given proper care and treatment, or destroyed. It should not be simply taken out of the flock and allowed to roam around the farm at will. A fowl that is very sick or of questionable value as a producer should be destroyed rather than given treatment. The presence of most infectious diseases and internal parasites can be best determined by autopsy of a dead fowl. It is a good practice, therefore, to make an examination of all that die or are killed on account of sickness. By such examination the presence of disease or parasites can be detected before they have made serious progress in UNIVERSITY OF CALIFORNIA — EXPERIMENT STATION the flock. All dead fowls should be disposed of by burning or deep burial in a place to which the fowls do not have access. Sanitation is essential for the maintenance of health in any flock. Under this heading is included cleanliness and the application of dis- Fig. 1. — Chicken-pox; cockerel. Natural infection. infectants and parasiticides. Cleanliness is perhaps the most impor- tant of the three. By thorough cleaning, many of the disease germs and parasite eggs will be removed. Droppings of fowls are especially dangerous as a spreader of disease. It is quite important, therefore, that droppings either should be removed daily or roosts so constructed that the fowls do not have access to the droppings during the day. Litter should be removed and floors cleaned frequently. Drinking appliances should be emptied and cleaned daily. If moist mash is fed the troughs should be cleaned daily. Circular 251] POULTRY DISEASES AND PARASITES Disinfectant should be applied only after a thorough cleaning. If applied to a dirty house, it will not penetrate the accumulations of filth and therefore, little benefit will be derived. Disinfectants are most effective when applied in liberal amounts and sprayed with con- siderable force to all parts of the house from all directions so that the bottom of cracks will be reached. Most disinfectants cannot be relied upon to destroy parasites such as mites and ticks, for which purpose oily preparations are more effective. A ' ' compound solution of cresol ' ' containing 50 per cent cresylic acid is a very reliable disinfectant. There are many such preparations marketed under various trade Fig. 2. — Chicken-pox; baby chick. Natural infection. names. The coal tar "sheep dips" are cheapest and quite effective. The "phenol coefficient" which is usually given on the container is an index of the efficiency of such products. Preparations, such as crude carbolic acid, are variable in their germicidal properties and, therefore, are not reliable disinfectants. CHICKEN-POX AND CANKER OR AVIAN DIPHTHERIA Chicken-pox is manifested by small wart-like growths on the comb, wattles, or skin of the head, and by the formation of masses of cheesy material or canker in the eyes and the mouth. Although these last named lesions are entirely different in character from the lesions on the skin they are due to the same cause, namely, the virus of chicken- b UNIVERSITY OF CALIFORNIA EXPERIMENT STATION pox.* This disease cannot occur unless the chicken-pox virus is present, although unsanitary conditions and poor methods of care and housing make it more likely to occur. Outbreaks of chicken-pox vary greatly in severity. In some flocks but a few birds may be affected and practically no loss result, while in other flocks the lesions may be very severe ; it may spread through Fig. 3. — Canker-eye, from natural infection with chicken-pox virus. almost the entire flock and cause a very great loss, both from decreased egg production and from the death of the infected fowls. In outbreaks in which a large percentage of the infected fowls have canker the loss will be greater than in flocks in which the lesions are largely on the skin. * Lesions in the mouth and eyes identical in appearance to canker may be caused by injury to the mucous membrane. Therefore, individual cases of canker may be due to a particle of litter, barley awn, weed seed, or similar material be- coming lodged in the corner of the eye, the cleft in the roof of the mouth or in the larynx. Circular 251] POULTRY DISEASES AND PARASITES For the treatment and prevention of chicken-pox and canker, vacci- nation is believed to be most effective. The use of the chicken-pox vaccine has been very extensive in this state for several years past and the results obtained from vaccination have been very satisfactory. One treatment is usually sufficient to check the spread of the disease in slightly infected flocks, although a second treatment is sometimes required. In badly infected flocks a second treatment given seven days after the first is always advised. Vaccine should be used on all birds in the flock as soon as the presence of chicken-pox in the flock is Fig. 4. — Chicken-pox and canker of the eye, from natural infection with chicken- pox virus. noticed. It is never recommended to vaccinate fowls before the appear- ance of the disease among them. The reason for this recommendation is that the length of time after vaccination that fowls are protected against the disease is variable and after healthy flocks are vaccinated there is therefore no assurance that they will be protected longer than three or four months. If a flock is divided into a number of small pens and are under close observation, it may not be necessary to vac- cinate the entire flock upon the appearance of the disease but only the UNIVERSITY OF CALIFORNIA EXPERIMENT STATION Figs. 5 and 6. — Chicken-pox; turkey. Natural infection. Circular 251] POULTRY DISEASES AND PARASITES pens that are affected. In such cases the vaccine would be used on other pens as soon as the disease appears. If the vaccine is properly administered it does not seem to have any harmful effect on the general condition of the birds. The egg yi^ld, however, is usually somewhat decreased for a short time after vaccination, but as a rule this decrease will be no greater than would be expected if the fowls were handled for any other reason. The vaccine is administered by injection beneath the skin with a hypodermic syringe. The dose is one cubic centimeter for each bird. Fig. 7. — Canker of the mouth, turkey; from natural infection with chicken-pox virus. The most convenient place for administration is beneath the skin of the breast, under the right thigh, the skin at that point being compara- tively free from feathers. When the operator holds the bird the left wing is held back, the foAvl laid on its left side, and the right wing and leg and feet held back with the last three fingers of the left hand. The exposed skin is then cleansed with a piece of absorbent cotton saturated with a disinfectant solution (2 per cent compound solution of cresol) and picked up with the thumb arid forefinger of the left hand. Then with the right hand the syringe needle is inserted just beneath the skin and the proper dose injected. With a little practice, one man with an assistant to catch the birds can vaccinate from 100 to 150 birds per hour. When an assistant holds the bird, both wings are grasped with the left hand and both legs with the right hand. The bird is then 10 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION laid on its left side with the breast towards the operator. The operator standing a little to the rear of the bird, cleanses the skin at the point of injection, picks it up with the thumb and forefinger of the left hand, and with the right hand inserts the syringe needle just beneath the skin and injects the vaccine. By this method a man with two assist- ants to catch and hold the birds, can vaccinate from 200 to 300 birds per hour. Fig. 8. — Method of holding a fowl and injecting chicken-pox vaccine. Fig. 9. — Materials required for vaccination. Circular 251] POULTRY DISEASES AND PABASITES 11 lu inserting the needle strict precaution should be taken that it go just beneath the skin and not at all in the breast muscle. The safest practice to follow is to have a sufficient area of skin exposed so that the point of the needle will always be in sight through the skin before any vaccine is injected. A syringe of 6 to 12 c.c. capacity is well suited for this work. The needle should be 16 to 18 gauge and from iy 2 to 2 inches in length. A screw needle is preferable. Vaccine deteriorates rapidly and should be used within seven days of its manu- Fig. 10. — Method of holding a fowl and removing canker from the mouth. facture. If old or decomposed vaccine is used, poor results will follow. Vaccine should be kept in a cool place, preferably on ice, until used and only one bottle opened at a time. The materials required for vaccination are : the vaccine ; a syringe which should be sterilized by boiling before using; a small wide- mouth, covered vessel, such as a quarter-pint milk bottle provided with a stopper, or a jelly glass with a tight fitting cover, which is used as a vaccine container from which to fill the syringe and which should be sterilized by boiling before using; a pan of disinfectant; and a piece of absorbent cotton for cleansing the skin at the point of in- 12 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION jection. The bottle of vaccine should always be thoroughly shaken before any vaccine is poured out and the wide-mouth container should always be thoroughly shaken before filling the syringe. The immunizing effect of vaccine does not take place immediately. Therefore, fowls infected at the time of vaccination or which become infected soon after will develop chicken-pox lesions. Such cases are usually mild and will soon recover if the fowls are removed from the flock and the lesions treated. Fig. 11. — Method of holding a fowl and removing canker from the eyes. All diseased birds should be removed from the flock and kept in comfortable quarters where they can be given treatment at two- or four-day intervals. The scabs which form on the growths on the comb, wattles, or skin should be removed with a dull knife or a pair of forceps, and tincture of iodine applied to the exposed suface. Col- lections of cheesy material in the mouth should be removed with forceps and tincture of iodine applied. Collections of cheesy material within the eyelids should be removed by pressing around the eye with the thumb and finger tips and tincture of iodine applied. If the cheesy material adheres to the eyeball, it will be necessary to use forceps Circular 251] POULTRY DISEASES AND PARASITES 13 to remove it. In such cases the eyeball is usually destroyed before the recovery is complete. Tincture of iodine can be applied most con- veniently and effectively with a medicine dropper. It will not in any way injure the eyesight or be otherwise injurious to the birls. The ad- ministration of vaccine in addition to local treatment with iodine will hasten recovery and decrease the loss from death. All diseased fowls should be given two or more doses of vaccine.* Fig. 12. — Fowl with roup. COLDS AND ROUP "Colds" are manifested by a discharge from one or both nostrils. When this discharge collects in the nasal passages it is rapidly trans- formed into a cheesy mass which causes a marked swelling of the face just beneath the eyes. This stage of the disease is called "roup." It can be easily seen that ' ' roup ' ' is merely the result of a cold. If fowls did not get "colds," they would not have roup. As a rule, "colds" and roup are confined entirely to the nasal passages, although in many * Chicken-pox vaccine can be obtained from the Division of Veterinary Science, University of California, at the actual cost of production, provided the applicant furnishes satisfactory evidence that chicken-pox exists among his fowls. The present cost of vaccine is l%c per dose. Hypodermic syringes with which to administer the vaccine can also be procured from the University at a cost of $3.50 each. All applicants should specify in writing the amount of vaccine desired or the number of fowls to be treated. Vaccine will be shipped only when cash accompanies the order, or C. O. D. When possible, orders will be shipped the same day they are received. 14 UNIVERSITY OF CALIFORNIA — EXPERIMENT STATION cases the eyelids may become closed by the large swellings beneath them. Seldom, however, are the eyes affected in any other way. This disease is usually the result of housing or weather conditions and not due to any specific infection. Therefore, it is not liable to spread through a flock by contact with diseased birds, nor is it liable to seri- ously affect any flock that it properly housed and cared for. Improper Fig. 13. — Method of relieving "stoppage of the tear duct," commonly called "cold in the eye." housing conditions are probably the most common cause of colds. Common faults in housing conditions are, presence of cracks in the walls back of the roosts, poor ventilation, overcrowding, dampness, and insanitation. Extended periods of damp, cold weather, or periods during which there is a wide variation in temperature during the day and night, are apt to cause ' ' colds ' ' to become prevalent. Prevention consists in correcting any faults in the housing conditions, giving the birds proper care, and keeping the premises sanitary. Circular 251] POULTRY DISEASES AND PARASITES 15 A satisfactory treatment for individuals consists in cleaning out the nostrils by pressing with the fingers and cleaning out the cleft with absorbent cotton on forceps or a match, and applying a drop of tincture of iodine in each nostril and in the cleft. This treatment should be repeated every three or four days. The treatment for roup is more difficult. This consists in opening the swelling with a sharp knife, removing the mass of cheesy material and packing the cavity with absorbent cotton saturated with tincture of iodine. The packing should be removed, the cavity cleaned and a new pack put in every five to seven days. If, upon removing the pack, no more cheesy material is found to have formed, the pack may be left out and the wound allowed to heal. If a large percentage of the flock have colds the following treat- ment may be used. Give Epsom salts in the drinking water, using one pound for each 125 adults or 200 to 400 birds under five months of age. The birds should have access to no other drink while the solution of Epsom salts is consumed. Following this, potassium per- manganate may be added to the drinking water in sufficient quantity to produce a deep purple color. This should be replaced by fresh solution when the color changes to brown. Some tonic, such as the following, may be added to the mash : Pulverized gentian 1 lb. Pulverized ginger % lb. Pulverized saltpeter y± lb. Pulverized iron sulphate % lb. Pulverized nux vomica *4 lb. Add one ounce of this mixture to each five pounds of mash and feed until the flock has recovered. If faulty housing is causing colds reliance should not be placed on the treatment just described. NUTRITIONAL DISEASE RESEMBLING ROUP A disease very similar to roup in manifestation, which may affect a large percentage of a flock at one time, may be due to nutritional factors. The symptoms of this disease are weakness; emaciation; a discharge from one or both nostrils which may be followed by a swell- ing of the face beneath the eyes ; a discharge from the eyes which may glue the eyelids together and 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 a yellowish white, round, cheesy pustule-like patches in the mouth and throat of about the size 16 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION Fig. 14. — Typical appearance of fowls with the nutritional disease resembling roup. Fig. I".. -Cheeky materia] m the eye of a fowl with the nutritional disease resemoling roup. Circular 251] POULTRY DISEASES AND PARASITES 17 Fig. 16. — Fowl with nutritional disease resembling roup with throat oesophagus opened to show the pustule-like lesions typical of the disease. and 18 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION Fig. 17. — Kidneys of a fowl with nutritional disease resembling roup. Circular 251] POULTRY DISEASES AND PARASITES 19 of a pinhead; and occasionally by the formation of masses of white cheesy material in the cleft or elsewhere in the mouth. This disease may be distinguished from chicken-pox by the absence of yellow color in the cheesy material and by the small size of the patches and color of the cheesy material in the mouth. It may be distinguished from "colds" and roup by the lesions in the eye and mouth, in addition to nasal discharge and swelling of the face. Postmortem examination of dead birds usually shows the kidneys to be very pale and marked with a network of very fine white lines. Occasionally there is also found a deposit of a white material on the surface of the liver, on the membrane around the heart, or elsewhere on the surface of the organs. It has been very definitely determined that this disease may result from insufficient supply of greens. It may occur even though the birds may be fed green food if the amount is insufficient. It has also been found in flocks which had access to growing greens, but which were at a distance from the poultry house. In these cases some of the fowls were getting a sufficient supply of greens but most of them were not going far enough away from the house to get it. This condition can usually be readily controlled by giving the birds all the green food they will eat. There may be other factors involved in producing this disease and it is, therefore, also advisable to dilute the mash by adding wheat bran. FOWL CHOLERA ASSOCIATED WITH RUPTURED EGG YOLKS This disease usually occurs among flocks of pullets during the period of heavy production. It is manifested by a rather small but steady loss of birds. The infected fowls are usually sick but a very short time before death occurs and in a great many cases are found dead rather than sick. The symptoms of the sick birds are droopiness, diarrhoea, discolor- ation of the comb, usually followed by death within twenty-four hours. Birds may be found dead in the nests or on the dropping boards under the roosts. The fowls affected are those that are laying well. The post-mortem examination of dead birds usually shows an en- larged, soft liver which may have minute yellowish white spots ; some- times small blood spots in the fat at the base of the heart or on the gizzard; sometimes inflammation of the intestines; and practically always egg yolk free in the abdominal cavity. The egg yolk may be like one freshly broken or may be in the form of a cheesy mass. In many of these fowls the presence of fowl cholera germs can be demon- 20 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION strated. The germs found in such cases, however, are of such low virulence that death can rarely be caused by feeding or inoculating healthy birds with them. This disease appears to be the result of heavy feeding and produc- tion, rather than entirely to infection with the fowl cholera germ. Good success in controlling this disease has been obtained by adding wheat bran to the mash to make it bulkier. This will automatically reduce the amount by weight of mash consumed and should also decrease egg production. If the losses have been very heavy the mash Pig. 18. — Tuberculosis nodules on the intestines and liver of a fowl. should be entirely replaced by bran until losses stop. If, however, not many birds are dying, the mash can be made one-half bran. It is also advisable to thoroughly clean and disinfect the houses and to use potassium permanganate in sufficient amount to give the drinking water a claret color, or to use some similar disinfectant in the drinking water. A one to two-thousand solution of bichloride of mercury is effective and safe. This must be used only in wood, glass, or earthen- ware vessels and must be kept away from other animals or from children. TUBERCULOSIS This disease is caused by a specific germ and cannot be produced in any other way. Symptoms of infection with this germ are appar- ent only in advanced cases, viz., marked emaciation, paleness of the comb, skin, or shanks. Circular 251] POULTRY DISEASES AND PARASITES 21 The lesions of tuberculosis consist of round yellow spots varying in size from a pinhead to a pea in the liver and spleen, and nodules varying in size from a pea to a small walnut on the intestines or on the membrane which holds the intestines in place. Lesions also occur less frequently in the kidneys, lungs, skin, and bones. Tuberculosis spreads by fowls eating substances, such as food and soil contaminated by the discharges from the infected birds. The loss Fig. 19. — Fowl showing a positive reaction to the tuberculin test. from tuberculosis is not apt to be great at any one time, but it will be constant and becomes increasingly severe as time goes on. There are two possible methods of eradicating tuberculosis from a flock. The first consists in disposing of all birds in the flock, thoroughly cleaning and disinfecting the house, leaving the yards vacant for a period of a few months and starting in again with new stock. If the yards are left vacant during hot or dry weather one or two months is sufficient. If, however, the ground is moist, from six months to a year may be required for the germs to die out. This is 22 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION the most practical method to use in small flocks or flocks which are raised solely for egg production. The other method of eradicating tuberculosis is by means of the tuberculin test. This test is made by injecting y 15 to y 2 n cubic centimeter of substance known as tuberculin into the skin of the wattle. If an injected bird has tuberculosis the wattle will swell. It is necessary to make repeated tests at intervals of about six months to entirely free a flock from tuberculosis by this method. Following each test all reacting birds must be removed from the flock and the houses given a thorough cleaning and disinfecting. It is recommended to use this test only in flocks that are valuable as breeders. COCCIDIOSIS This is an infectious disease of chicks caused by the presence of minute parasites in the intestines. It may affect the chicks between the ages of two weeks and six months, but more commonly it occurs in birds four to eight weeks old. The usual history of outbreaks of coccidiosis is that the chicks do well until they are a few weeks old, when they begin to look unthrifty, droop and gradually die. The symptoms observed are ruffled feathers, paleness of the skin on the heads and shanks, and an inclination of sick chicks to separate them- selves from the flock and stand "humped up" with their eyes closed for hours at a time. Diarrhoea which may be bloody is sometimes present. A bloody diarrhoea can be considered as positive evidence of coccidiosis. Other symptoms are not so characteristic of this disease. Post-mortem lesions usually consist of an enlargement of the ceca or "blind pouches" of the intestines. The contents may be either normal in consistency and brown or reddish brown in color, semi- liquid and bloody, or solid and yellowish white, brown or red in color. Frequently there is an inflammation of the lining of the intestines throughout their entire length. Other organs are in most cases apparently normal. The disease is spread by chicks drinking water or eating food, litter or soil contaminated by the droppings of diseased chicks. It has been demonstrated that these parasites will remain alive in soil for a year or more. Therefore, chicks allowed to run in yards in which infected chicks were kept the preceding year are very liable to become infected. Thus far no practical method of treating the soil to destroy these parasites has been developed. This disease can be prevented and out- breaks controlled by proper feeding methods and proper sanitation in the brooder houses. Circular 251] poultry diseases and parasites 23 Fig. 20. — Typical appearance of chicks with Coccidiosis. Pig. 21. — Ceca or blind pouches of the intestines of a normal chick and en- larged ceca of a chick with Coccidiosis. 22 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION the most practical method to use in small flocks or flocks which are raised solely for egg production. The other method of eradicating tuberculosis is by means of the tuberculin test. This test is made by injecting y 15 to % cubic centimeter of substance known as tuberculin into the skin of the wattle. If an injected bird has tuberculosis the wattle will swell. It is necessary to make repeated tests at intervals of about six months to entirely free a flock from tuberculosis by this method. Following each test all reacting birds must be removed from the flock and the houses given a thorough cleaning and disinfecting. It is recommended to use this test only in flocks that are valuable as breeders. COCC1DIOSIS This is an infectious disease of chicks caused by the presence of minute parasites in the intestines. It may affect the chicks between the ages of two weeks and six months, but more commonly it occurs in birds four to eight weeks old. The usual history of outbreaks of coccidiosis is that the chicks do well until they are a few weeks old, when they begin to look unthrifty, droop and gradually die. The symptoms observed are ruffled feathers, paleness of the skin on the heads and shanks, and an inclination of sick chicks to separate them- selves from the flock and stand "humped up" with their eyes closed for hours at a time. Diarrhoea which may be bloody is sometimes present. A bloody diarrhoea can be considered as positive evidence of coccidiosis. Other symptoms are not so characteristic of this disease. Post-mortem lesions usually consist of an enlargement of the ceca or "blind pouches" of the intestines. The contents may be either normal in consistency and brown or reddish brown in color, semi- liquid and bloody, or solid and yellowish white, brown or red in color. Frequently there is an inflammation of the lining of the intestines throughout their entire length. Other organs are in most cases apparently normal. The disease is spread by chicks drinking water or eating food, litter or soil contaminated by the droppings of diseased chicks. It has been demonstrated that these parasites will remain alive in soil for a year or more. Therefore, chicks allowed to run in yards in which infected chicks were kept the preceding year are very liable to become infected. Thus far no practical method of treating the soil to destroy these parasites has been developed. This disease can be prevented and out- breaks controlled by proper feeding methods and proper sanitation in the brooder houses. Circular 251] POULTRY DISEASES AND PARASITES 23 Fig. 20. — Typical appearance of chicks with Coccidiosis. Fig. 21. — Ceca or blind pouches of the intestines of a normal chick and en- larged ceca of a chick with Coccidiosis. 24 UNIVERSITY OF CALIFORNIA — EXPERIMENT STATION The method of feeding to prevent the occurrence of the disease con- sists in keeping sour milk or butter-milk constantly before the birds from the time they are put in the brooder, and feeding sparingly of grain and mash. If the amount of grain and mash fed is not restricted, coccidiosis is liable to develop, even though sour milk is fed all the time. The disease frequently occurs in previously healthy flocks follow- ing sudden changes in the kind of grain and mash fed. Such changes should, therefore, be avoided. Coccidiosis also often appears soon after an exceptionally cold night or following a severe storm which has caused the brooder to become cold or damp. It is essential, therefore, that houses be kept clean and dry and that adequate temperature be maintained at all times. To control outbreaks of the disease no mash and very little grain should be fed. The bulk of the grain fed should be given at night so that the chicks will have a fairly full crop when they go to bed. A small amount of grain may be fed in the morning, but the greater part of the food in the daytime should consist of sour milk or butter-milk which is kept before them constantly. The houses should be very thoroughly cleaned and covered with a thin layer of chopped straw or shavings litter. Feeding large amounts of sour milk will cause the droppings to become very profuse and watery. In order to keep the floor clean and dry the litter should, therefore, be renewed daily. Abundant warmth should be maintained both under the hover and in the brooder rooms. This feeding method should be continued until losses stop and the general condition of the flock has improved. This usually will not require more than a week or ten days. After this time the mash may be again fed but the amount should be small and increased very grad- ually. Although no experiments have been made it is thought that some of the better varieties of sour milk substitutes, such as semi-solid butter-milk, will give as good results as butter-milk. Other remedies which have been recommended are hydrochloric acid, one teaspoonful to one quart of water, potassium bichromate 1 to 5000 solution, and crude catechu 1 to 4000 solution. The solutions of the above chemicals are substituted for the drinking water. If any of these are used the amount of mash fed should be reduced. Circular 251] POULTRY DISEASES AND PARASITES 25 WHITE DIARRHOEA OF CHICKS Disease manifested by diarrhoea is of common occurrence in young chicks. Since the discharges from the intestines in such cases are light- colored, any trouble of this nature is usually designated as "white diarrhoea." White diarrhoea may be caused either by infection with a specific germ or by some error in incubation or brooding. Infectious white diarrhoea, which is known as "bacillary white diarrhoea," is caused by a germ and cannot be produced in any other way. The symptoms are usually the same whether the disease is infectious or not infectious. "Bacillary white diarrhoea" occurs in chicks hatched from eggs produced by infected breeding stock. Chicks which are infected with bacillary white diarrhoea and do not die, continue to harbor the germs throughout their lifetime. Such hens do not show any indication of infection ; are apparently in perfect health and are often good layers. They therefore frequently get into breeding flocks. Eggs produced by such hens contain the germs on the inside. The chick hatched from such an egg will be infected when it comes out of the shell and may quickly spread the infection to other chicks in the incubator. The disease usually appears during the first week but losses may continue for three or four weeks. The mortality is usually high, on an average more than 50 per cent. There is no satisfactory method of treating bacillary white diarrhoea. Sanitary precautions, such as removal and destruction of the sick and dead chicks, thorough clean- ing and disinfection of the brooders, and dividing of the remaining chicks into small units, will assist in reducing the mortality. There are no drugs which are of any value for this purpose. Bacillary white diarrhoea can be prevented by using only eggs for hatching which are known to be produced by a flock free from the infection. If a poultry breeder has had no trouble with bacillary white diarrhoea in his own chicks or in chicks hatched by others from eggs produced by his flock, this may be taken as evidence that his flock is not infected. It is also possible to determine whether or not a flock is infected by means of a blood test. This test must be made in a laboratory with a sample of blood procured from the bird. It is advisable to have such a test made on all new breeding stock unless it is known that the flock from which the stock was procured is free from the infection. White diarrhoea that is due to errors in incubation and brooding can not be differentiated by symptoms or post-mortem appearance from infectious white diarrhoea. Therefore, to determine positively whether 26 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION Figs. 22 and 23. — Securing blood for the agglutination test for bacillary white diarrhoea infection in breeding stock. Circular 251] POULTRY DISEASES AND PARASITES 27 or not infection is present, it is necessary to have a bacteriological examination made. Among errors in incubation or brooding which may cause diarrhoea are, overheating or chilling in the incubator, overheating or chilling in the brooder, and too early and improper feeding. The most effective means of treating chicks with non- infectious white diarrhoea is to give them the best possible care and proper food. The use of sour milk or butter-milk is always advisable. LEG WEAKNESS OF CHICKS Leg weakness is generally considered to be caused by improper feeding. The possible errors in feeding are feeding too much, feeding a ration insufficient in mineral matter, or feeding a ration lacking iu fiber. Lack of exercise or confining the chicks in the houses is also thought to be a contributory factor in producing the disease. It is unlikely to occur if flocks are fed a properly compounded ration, are not crowded in the brooder house, and are allowed to run out of doors early. When the disease does occur it may be controlled by making changes in the ration and the method of handling. If the ration is too rich or does not contain enough fiber, it may be corrected by adding wheat bran. As the amount of bran to be added varies with the con- ditions a general recommendation would be to use equal parts of the mash and bran. Mineral matter may be supplied by sprinkling pre- cipitated calcium phosphate over the surface of the mash after it has been put into the trough or hopper. An abundance of green food should always be provided. If the chicks have been confined in the houses they should be allowed to run outdoors every day that the sun is shining. They should, of course, not be kept out when they show evidence of being chilled, but they can be put out for at least a few minutes each day and the time can be lengthened as the chicks become accustomed to being outdoors. BLACKHEAD IN TURKEYS The cause of this disease is a small parasite present in the intestines and liver of diseased birds.* The birds become infected by eating soil, food, water, etc., contaminated by the droppings of diseased birds. The disease is most dangerous to birds between the ages of two weeks and six months. The symptoms are droopiness and diarrhoea. The head may or may not become dark in color. On postmortem exam- * Smith and Graybill, in their experiments with blackhead, found it impossible to produce the disease in turkeys by feeding infective material unless cecum worms were present in the ceca. 28 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION ination yellow circular spots amy be found on the liver and ulcers in the walls of the blind pouches of the intestines. It is frequently impossible to find any lesions in young poults which die from black- head. Birds which do not die from the disease are apt to be carriers of the parasite as long as they live and it is by this means that the disease is usually transmitted to young turkeys. If young turkeys are kept on ground which has been contaminated by an infected flock or brooded by hens which have survived an outbreak of the disease, they are very liable to become infected. Success in controlling the disease among turkeys raised in con- finement has been obtained bv the following feeding method: After n INCHES Z~i +— Knfec-' - — -2__, — j — , — jf • \ SELr - jF *fe *fj 1 mm r A «T - y \ fc§L -. y : m ■ Jr Fig. 24. — Lesions of blackhead in the liver of a turkey. the turkeys are old enough to leave the brooder their food consists entirely of sour milk or butter-milk kept before them all the time, and a restricted amount of whole gratoi. No mash or water is allowed. By following this method turkeys have been successfully raised in contaminated yards for several years. This method would be difficult to apply in turkeys raised on range. For controlling the disease among birds raised on range, ipecac has recently been highly recommended by a turkey raiser of this state. Circular 251] POULTRY DISEASES AND PARASITES 29 This is administered, as follows : To each unit of 20 turkeys give two teaspoonfuls of powdered ipecac in the mash, twice a week from the time the birds are two weeks old until three months old. After that time the dosage may be reduced to one teaspoonful every ten days for the same unit of turkeys. It was also claimed that tincture of ipecac administered in five-drop doses three times daily was valuable for the treatment of visibly sick birds. Fig. 2o. — Ulcers in the Avails of ceca or blind pouches of a turkey with blackhead. 30 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION COMMON DISEASES OF BIRDS Most ' ' common ' ' or non-infectious diseases of birds are of an intes- tinal origin, that is, due primarily to indigestion. Therefore, many birds that become droopy and which would die if left alone may recover if treated properly. It is a good practice to remove all droopy birds from a flock and give them one-half or one ounce of castor oil. Castor oil can be safely given through a rubber tube attached to the nozzle of a hard-rubber veterinary dose syringe of a suitable capacity and passed down the throat into the crop (Fig. 26). If the practice Fig. 26. — A safe method of administering caster oil or other liquid medicine to a fowl. ClECULAR 251] POULTRY DISEASES AND PARASITES 31 of giving castor oil to all droopy birds is followed, the mortality can be greatly decreased. It is always advisable to remove any sick birds from the flock, no matter what the cause of the sickness may be. If this practice is strictly adhered to it will be a great assistance in con- trolling any infectious disease which may occur in the flock. LICE These insects can be distinguished from all other parasites on the body by the fact that they have three pairs of legs and their bodies, divided into three sections, the head, thorax, and abdomen, are flat- tened dorso-ventrally, i.e., as if a flattening force had been applied on their backs. They are seldom over % 6 of an inch in length and of a yellow or grayish color, sometimes ornamented with dark stripes but never uniformly dark brown or red. Parasites of these latter colors may be fleas, mites, or ticks. The entire life of lice, including the egg stage, is spent on the body of the birds. It is only by accident that the parasites leave their hosts except to migrate to other hosts of the same species. The eggs require about a week to hatch after which maturity is reached in about two weeks. None of the present-day remedies are harmful to the egg stage. This necessitates the use of a substance that will remain on the body long enough to kill the emerging young, or a repetition of the treat- ment between 8 and 14 days after the first treatment. Sodium fluoride* is the only remedy that answers the first require- ment of eliminating all the lice with a single treatment. It also has the advantages (1) of being safe to both birds and operator, (2) of accomplishing a complete elimination of the lice, and (3) of being suitable for baby chicks and setting hens. No other treatment com- bines these advantages, for which reason we restrict our recommenda- tions to this single remedy. Sodium fluoride may be obtained from drug stores as a white powder (commercial form) or as crystals (chemically pure). It may be applied in three ways, viz., by the " pinch method," dusting, and dipping. The "pinch method" consists of placing on the skin of each fowl approximately ten ''pinches" (amount held between thumb and fore finger) of the commercial sodium fluoride, distributed on the breast, eaoh thigh, below the vent, on each side of the back, on the neck, on * This treatment was introduced and is highly recommended by the Bureau of Entomology of the U. S. Department of Agriculture. The writers have used it repeatedly with unvarying success. 32 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION the head, and finally one sprinkled on the underside of each outspread wing. The birds, when treated, should be held over a shallow pan or newspaper in order that the excess of the chemical may be saved. Dusting. — The powdered sodium fluoride is sometimes mixed with three or four times its bulk of flour or talc and applied with a large shaker, ruffling the feathers of the bird as the chemical is applied. This procedure is not as economical of material or as efficient as the pinch method and the excess of chemical in the air is irritating to birds and operators. Fig. 27. — Three common species of poultry lice. Dipping in sodium-fluoride solution is rapidly becoming a standard method of treatment among a large group of producers that have over- come the poultrymen's prejudice against wetting their birds. In California, birds may be dipped safely in almost every month of the year by choosing a warm day with little wind and completing the operations an hour or two before sundown in order that the fowls may dry thoroughly before roosting for the night. The solution should be prepared in a wooden container, avoiding contact with gal- vanized iron. The ordinary wooden wash tub is excellent for this purpose. One ounce of the commercial sodium fluoride, or two-thirds of an ounce of the chemically pure crystals, should be dissolved in each gallon of tepid water. The best method for dipping the birds is to hold them with the left hand by both wings. They are then placed feet foremost in the warm dip and submerged until only the head remains above the surface. They should be held in this position from 20 to 25 seconds while the feathers are ruffled to permit penetration of the liquid. Just before removal, the head should be ducked under the surface. The birds should be held above the clip for two or three seconds to allow them to drip before releasing them. One hundred Circular 251] POULTRY DISEASES AND PARASITES 33 birds will use up approximately five gallons of dip, on which basis material should be available at the start of operations to keep the dip replenished. The dipping method kills all lice immediately but where it is applied as a powder three or four days will pass before elimination is complete. If the birds are caught and handed to the operator, from 100 to 125 birds an hour can be treated by dipping or dusting, and approximately 60 to 75 per hour by the "pinch" method. Prevention is accomplished to some extent by supplying the birds with ample dusting boxes filled with fine road dust to which sulfur or tobacco dust has been added. The best advice, however, is to treat all new acquisitions to the flock before permitting them to mix with the clean birds. Brooding hens, unless definitely known to be free from lice, should be treated before being placed with newly hatched chicks. Spraying the house and roosts has little effect on the lice problem. MITES Two distinct groups of mites attack poultry. One group is migra- tory, passing the greater portion of its life, not on the birds, but in cracks and crevices about the poultry houses from which they make nightly raids upon the roosting poultry to suck blood. The other group passes its entire life history on the birds by burrowing beneath the scales of the legs, into the skin at the base of the feathers, or into the shaft of the feathers themselves. The Scaly Leg Mite. — This parasite gets its name from its habit of burrowing beneath the scales of the leg where its presence and activi- ties cause a lifting of the scales and a swollen condition of the shank which, in advanced cases, amounts to so pronounced a distortion and deformity that the affected birds are unable to walk. The mites them- selves are microscopic and the poultry-man generally makes a diagnosis of the trouble by observing the symptoms noted above. Treatment consists of dipping the legs of the birds in a mixture of equal parts of crude oil and raw linseed oil, taking precautions to avoid wetting the legs above the scaly portion. This treatment should be repeated in about three weeks unless marked improvement is noted. This is, however, seldom necessary. Prevention. — The legs of newly acquired birds should be observed carefully in order that infected birds may be segregated and treated before being placed with the clean flock. The Depluming Mite is a microscopic parasite which burrows into the skin at the base of the feathers, producing an intense itching which 34 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION causes the birds to pluck out the feathers, leaving nude areas at the more severely infested places. No general treatment is available, but individual birds may be cured by the thorough application at intervals of about five days, of a sulfur ointment made by mixing three parts of flowers of sulfur with one part of lard. The Common Chicken Mite is a small grayish red mite, approxi- mately of the size of a pinhead when filled with blood. It may be Fig. 28. — Photomicrograph of the scaly leg mite. distinguished from the insect parasites by its four pairs of legs, in place of the insects ' three, and by the fact that its body is not divided into separate subdivisions. Its food is blood which it draws from the birds by means of long piercing stylet-like mouthparts. Unlike the other mites mentioned above, it hides away during the day in cracks and crevices about the hen house, migrating to the roosting birds at night to suck blood. The experienced poultry-man is warned of their presence by the "salt and pepper'' marks on the roosts, tiny circular black and white dots slightly smaller than "fly specks" caused by Circular 251] POULTRY DISEASES AND PARASITES 35 the excrement of the mites. However, if present, even a cursory examination of a few cracks or crevices in the vicinity of the roosts will reveal myriads of these mites. Control. — Inasmuch as the mites are seldom found on the bodies of the birds during the day, except in the first feeding period when they sometimes remain attached for a night and a day, or in dark nest boxes, control measures are directed most advantageously against the hiding places. A thorough clean-up of the premises to which the birds have access, together with the elimination of every useless article therein, such as boxes, coops, boards, etc., is the first step. Old nesting Fig. 29. — The common poultry mite greatly enlarged. material should be burned and if the infestation is severe, roosts and nests should be dismantled to be replaced by construction that will facilitate future clean-ups. Methods must now be directed against the cracks and crevices of the floors, walls, and even the roof of the poultry house. In heavy infestations the mites sometimes migrate to the out- side of the house when the inside is sprayed. They should be looked for along the cracks on the outside and, if present there, a spraying of the outside will be decidedly worth while. The most efficient man- ner of accomplishing this end is by the use of liquid insecticides applied preferably by "bucket" or "knapsack" spray pumps. A coarse spray is most effective and should be applied to each area from several different angles to insure penetration into all hiding places. Many of the existing sprays are efficient. Any of the dips used on domesticated animals made up in a slightly stronger solution than 36 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION directed for the dipping of domesticated animals will give fairly satis- factory results. The most satisfactory of all applications, however, are the wood preservers similar to " CarboUneum" that have the coal- tar product anthracene oil as a base. These have the advantage of being effective over a long period and of soaking into the wood rapidly without leaving a greasy residue to soil the feet, feathers and eggs of the birds. They should be diluted about one-half with kerosene to facilitate spraying. One careful, thorough treatment generally proves sufficient with this type of spray. Crude oil diluted sufficiently with kerosene to make it easily sprayed is efficient in killing the mites and is sufficiently durable but leaves the roosts, floors, etc., in an oily condition so that the flock must be excluded from the treated premises for some time in order to avoid soiling of feathers and eggs. Whitewash containing 3 to 5 per cent of crude carbolic acid kills large numbers of mites but is not nearly as effective as anthracene oil or crude oil. Prevention. — The common chicken mite is introduced into clean flocks in many cases in contaminated shipping coops. In some cases the introduction may be accomplished by a few young mites that are engorging for the first time on the introduced fowls. To overcome this possibility, newly acquired birds should be kept in special coops for two or three days before being placed in clean houses. These coops should then be destroyed or disinfected with boiling water or with one of the sprays suggested above. Shipping coops from other poultry plants should not be left in or near clean houses, nor should second-hand equipment be introduced unless the proper precautions of disinfection are taken. Mites will live for from three to five months without food, a fact which should be considered when vacant buildings are to be occupied by clean flocks. In cases where the control of the mite is impossible owing to the character of the quarters or lack of them, some relief is afforded by wrapping the ends and other points of contact of the roosts which have been painted thoroughly with crude oil, with rags soaked in the same substance to prevent the mites from gaining access to the fowls after they have roosted. To make this procedure effective crowding should be discouraged and the back roosts should not be near enough to the wall to permit the movement of the mites to the plumage of the birds. Circular 251] POULTRY DISEASES AND PARASITES 37 TICKS These parasites are closely related to the mites but are always larger, easily visible to the naked eye and have a thick leathery cuticula or skin. The only tick attacking' fowls that is of economic importance is the so-called fowl tick or "blue bug." The adult tick is flat, egg- shaped in outline, dark brown in color, from V4 to %g of an inch in length and about half as wide at its widest part. Its habits are essen- tially like those of the common chicken mite referred to above. The ticks have a remarkable ability to live for long periods without food, the specimen photographed in figure 30 having lived in a tightly corked vial in the author's desk for a period of 16 months without food. Records are available of adult ticks that have fasted for 2% years. Fig. 30. — Ventral and dorsal view of the poultry tick or blue bug enlarged. Control — The procedure is the same as in the case of the common chicken mite, with the exception that the spray material should be stronger in every case when the dilution is made with water. The wood preservers of anthracene oil stand out as the most promising materials but treatment with these often has to be repeated at the end of. three or four weeks to insure entire control. If sheep dip or other stock dips are used their dilution should be at least as strong as four parts of water to one of dip. When individual fowls are heavily in- fested with larvae taking their first meal, when they remain attached for several days, it is advisable to dip them in a 2 per cent coal-tar dip in case the birds show signs of weakness. The best practice, however, 38 UNIVERSITY OF CALIFORNIA — EXPERIMENT STATION is to merely segregate the infested birds for a few days in an isolated coop until the ticks became engorged and drop off when the birds may be returned to the flock and the coop destroyed or disinfected with boiling water or some of the sprays mentioned above. Prevention. — The procedure here is also much the same as in the case of the common mite mentioned before. The period of quarantine mentioned for the previous mite must, however, be lengthened to five or six days in the case of the poultry tick, but may be eliminated entirely from the standpoint of tick prevention by a careful exam- ination of the thighs, breast and sides for the round bluish-red larval ticks that can be easily seen on account of the contrasting color of their bodies and the skin of the birds. FLEAS These insects may be distinguished by their dark brown color, three pairs of legs, and their laterally flattened condition. The Sticktight Flea, although parasitic on dogs and cats, finds its best host in poultry. This flea remains attached to the host throughout its adult life. In poultry they are generally located about the eyes and comb. The eggs laid by these attached females fall to the ground and hatch, or in case the eggs are retained in the burrows or ulcers caused by the attached females, the larvae upon hatching fall to the ground. These larvae are tiny white, caterpillar-like organisms with chewing mouthparts. They subsist on the debris or manure on the floors of houses and yards. When they have become full-grown as larvae they spin a white coccoon in which they change from the larval stage to that of an adult, after which they attach themselves to the skin of their hosts to suck blood. The constant irritation, particularly in spots where they are present in large numbers, together with a slight burrowing activity on the part of the fleas, causes the formation of ulcers so extensive at times that blindness and subsequent death is produced. Control. — The first step in control is to prevent further infestation. This can be accomplished by a rigid clean-up of the floors of the houses and the pens, followed by a thorough spraying with kerosene, crude oil or kerosene emulsion. Nest boxes and dropping boards should receive similar treatment. Flooding the yards with irrigation water is said to produce beneficial results. Infested birds may be relieved by dipping in a 2 per cent Creolin solution. Other Fleas. — The cat and dog flea, the human flea, and the rat flea are frequent inhabitants of poultry houses. These fleas attach them- Circular 251] POULTRY DISEASES AND PARASITES 39 selves to their hosts only momentarily at the time that they suck blood, remaining unattached on the host's body or leaving it entirely between meals. The habits are otherwise like those of the "stick tight" men- tioned above. The control is also similar. One precaution that applies equally well to the sticktight flea is to "turn under" all manure and other scrapings from the poultry houses and yards that is to be used for fertilizing purposes. The mere storing of the manure outside the house in piles or spreading it on the fields will not prevent the develop- ment of the flea larvae, and although it will prevent them from gain- ing access to confined fowls, the cats, dogs and men of the neighbor- hood will be the alternative recipients of their attentions unless the manure is carefully turned under by plowing or spading. The bottoms of nest boxes should be frequently and liberally sprinkled with tobacco dust or pyrethrum powder. FLIES Life History. — The common house fly lays its eggs on freshly deposited manure. These hatch in about two days into tiny glistening white, footless maggots that grow rapidly for approximately a week until about a half inch in length, when they migrate from the moister part of the manure to a drier portion; here they turn into brown, barrel-shaped "pupae," from which they emerge as full grown flies in about four days. The blow flies, flesh flies, buzz flies or meat flies, as they are vari- ously called, will also breed in chicken manure, but prefer the bodies of dead birds left exposed on the ground or buried in shallow holes. When garbage is fed, unless extra precautions are taken, fly breed- ing will occur in the garbage itself and even in moist soil that has become saturated with nitrogenous material. Control. — Removal of the manure from the poultry houses and yards at intervals of less than seven days is the first essential. Its disposal may be accomplished in several ways. In truck and fruit regions it has a very definite cash value if protected from the rain and if the ' ' droppings ' ' — scrapings from the dropping board, and the "sweepings" — material from floors and yards, are segregated in fly- tight bins and collected at frequent intervals. Many producers accom- plish the same result by spreading the manure daily on plots to be fertilized in a thin layer that will rapidly dry out. The fly larvae will be destroyed by the drying but it should be plowed under about once a week to avoid the emergence of fleas. 40 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION The maggot trap is another very effective method of fly control where poultry manure is concerned. This consists of a concrete pan about 9' X 12' X 6" deep with 4" walls. This is kept filled with water to which a film of oil is added. A table with legs a foot and a half high and slightly smaller in area than that of the pan is placed in the pan. The top of the table is made of inch square pieces spaced their own width apart, leaving a latticed appearance, and covered with straw to prevent the manure from falling through. The manure is then placed on this table or rack and moistened enough to make it thoroughly wet but not dripping. Each addition is treated in the same way, the whole deposit being kept wet at all times. The fly larvae flourish under this treatment but when ready to pupate their search for a dry place ends invariably in a fall to the oil-filmed water in the pan below. If the mass of manure is kept wet, this method will return a hundred per cent efficiency. Dead fowls should be disposed of through the garbage collection system in cities or towns, but in the rural districts, incineration is just as effective. If it is necessary to bury dead animals, a hole at least a foot and a half deep should be prepared, the body covered with crude oil and the ground above well tamped. TAPEWORMS The effect of an infestation of tapeworms in poultry is so insidious that the cause is often either not suspected or entirely overlooked. These worms, inhabitants of the intestines, when full grown, range from almost microscopic size to ten inches, depending on the species. They have a ' ' head ' ' or scolex by which they attach themselves to the walls of the intestine. Behind this are a series of segments which have their origin just behind the scolex at the "neck." As these segments grow older and new ones are formed at the "head" end, they move away from this end and finally, when mature, i.e., when full of ' ' eggs, ' ' slough off and pass from the body of the host with its feces. If these "eggs" are eaten by some other animal which acts as an intermediary host, the young tapeworm develops up to a certain stage in its body, where it remains dormant until eaten by poultry, when the larval tapeworm again becomes active, further development takes place and the worm becomes mature, sloughing off more segments of mature "eggs." The Common Poultry Tapeworm is, as its name implies, our commonest tapeworm. Investigations at the Oklahoma Experiment Station have demonstrated apparently, without leaving any doubt, that the larvae of houseflies feeding in poultry manure become the Circular 251] POULTRY DISEASES AND PARASITES 41 intermediary hosts. Chickens become infested by eating these larvae or the adult flies that they become. Other Tapeworms. — Several other tapeworms are recorded from the United States. One is contracted by eating infected larval or adult stable flies, another through snails, one through slugs, and the hosts of the others are still in doubt, although dung beetles have been suggested. Control. — Where the flocks are confined to yards and houses from which the manure with its infected fly larvae is removed promptly, and efficiently disposed of, and where other intermediary carriers are not so apt to occur, little trouble results from tapeworms. Very Fig. 31. — Inside of a hen's intestine, showing attached tape worms, 2 X. (At post mortem examination, the worms appear much longer and more transparent, but contract and become whiter at death.) little has been done in regard to the treatment of poultry tapeworms. The Oklahoma Station recommends cooking a mash of one gallon (for 15 birds) of whole grain to which has been added a small tablespoon- ful of concentrated lye. After a fifteen hour fast, the cooled mash is fed to the birds, allowing them to eat as much as they wish and pro- viding plenty of water. The treatment may be repeatejd in twenty- four hours. They report exceedingly satisfactory results. Turpentine in !/4 to y 2 ounce doses administered to the birds individually, followed by a 40 to 50 grain dose of Epsom salts will also give good results if the number of fowls to be treated is small enough to make such indi- vidual treatment feasible. Freshly ground areca-nut in 30 to 50 grain doses is also said to be effective. Treatment is facilitated by mixing the required amount of the powder into pellets with butter or lard. 42 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION ROUNDWORMS This name is commonly applied to the slender wire-like worms from iy 2 to 3 inches long that are commonly found in the intestines. Affected pullets are stunted in growth and their plumage is bedraggled and soiled. Older hens, although seldom seriously affected, have a generally unkempt appearance and their egg production is below normal. The mature worms in the intestine deposit eggs which pass out of the body of the birds in the droppings. After a few days' exposure to the air a young worm develops in the egg which, if eaten by the bird, promptly hatches and soon becomes a mature worm in Fig. 32. — Section of intestine showing roundworms protruding from the cat ends. the bird's intestine. These eggs are very resistant and will persist in the ground in a healthy condition for months and even years. No practical treatment is known at present for destroying these eggs on infested ground. For this reason our greatest trust must be placed in the repeated treatment of the birds. Tobacco is the most successful remedy that has yet been found for removing these worms. It is generally administered in the form of ground tobacco dust mixed with the mash at the rate of one pound of dust to 50 pounds of dry mash, feeding this treated mash for from three to four weeks. Growing birds kept in infested yards may require a repetition at intervals of about six weeks. There is a great variation Circular 251] POULTRY DISEASES AND PARASITES 43 in the different tobacco dusts on the market, both in strength and origin, as some are sweepings from manufacturing plants, some are milled in combination with other substances, while the most desirable are 100 per cent ground tobacco. Tobacco dust also loses its strength by exposure to air or moisture, which necessitates buying in quantities just sufficient for the present need. Tobacco dust is now being gen- erally handled by feed stores and should be retailed in containers bearing the analysis of the amount of nicotine present. Work is now being carried on at this Experiment Station to deter- mine an exact treatment ; until this work is completed the above treat- ment is recommended wherever the nicotine content does not exceed 1.5 per cent, in which case the amount mixed with each 50 pounds of mash should be correspondingly reduced if laying hens are being treated, since an excess of tobacco will cause a reduction in the egg production. With young birds, however, a stronger dose and a corre- spondingly shorter period of treatment may be utilized with no harm- ful effects. Wherever possible chicks and young pullets should be on land that has not been occupied by hens for at least a year and their buildings carefully cleaned and washed before occupancy. Later troubles may be avoided if every flock of pullets suspected of having worms is given a thorough tobacco treatment before they commence to lay. Fig. 33. — Highly magnified eggs of cecum worm and intestinal round worm which pass out in the droppings and contaminate the yards. 44 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION CECUM WORMS These tiny parasites, measuring from y 2 to % of an inch in length, are found in the ceca or "blind guts" of the intestine. On account of their small size they are often overlooked by the poultryman or taken for the young of intestinal round worms and their harmful effects are minimized or ignored. Their presence on the walls of these organs interrupts their normal functioning and in the case of baby chicks, may result in death as early as the tenth day. On account of their sheltered position, they are very hard to remove. Large doses of tobacco dust have been known to cause their removal but no definite data on this point are available at the present time. Infection occurs in the same manner as outlined for the round worms and preventive measures should be taken with chicks and pullets along the same lines.