CALIFORNIA AGRICULTURAL EXTENSION SERVICE CIRCULAR 8 February, 1927 DISEASES AND PARASITES OF POULTRY IN CALIFORNIA J. R. BEACH AND S. B. FREEBORN PUBLISHED BY THE COLLEGE OF AGRICULTURE UNIVERSITY OF CALIFORNIA Cooperative Extension work in Agriculture and Home Economics, College of Agriculture, University of California, and United States Department of Agriculture cooperating. Dis- tributed in furtherance of the Acts of Congress of May 8 and June 30, 1914. B. H. Crocheron, Director, California Agricultural Extension Service. UNIVERSITY OF CALIFORNIA PRINTING OFFICE BERKELEY, CALIFORNIA 1927 CONTENTS PAGE Introduction 3 General preventive measures 3 Chicken-pox and canker or avian diphtheria 8 Infectious bronchitis 15 Colds and roup 18 Nutritional disease resembling roup 20 Ruptured yolk 23 Fowl cholera 25 Fowl typhoid 26 Tuberculosis 27 Coccidiosis 29 Bacillary white diarrhea of chicks 35 Leg weakness of chicks 39 Blackhead in turkeys 40 Common diseases of birds 45 Lice 46 Mites 48 Ticks 52 Fleas 53 Flies 54 Tapeworms 55 Roundworms 57 Cecum worms 60 Gizzard worms 60 Digitized by the Internet Archive in 2011 with funding from University of California, Davis Libraries http://www.archive.org/details/diseasesparasite08beac DISEASES AND PARASITES OF POULTRY IN CALIFORNIA 1 J. E. BEACH2 and S. B. FREEBOKN3 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 likelihood 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. Quarantine. — 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 are put with the others. Even with this precaution the presence of some infectious diseases, such as tuber- culosis, may be overlooked. Feeding. — Feeding methods are responsible for the sickness and death of birds in many flocks. Frequently losses from this cause are so numerous as to resemble the effect of an infectious disease. It is quite apparent, therefore, that proper feeding of fowls is an important factor in keeping fowls healthy. i This publication is a revision of Experiment Station Circular 251. 2 Assistant Professor of Veterinary Science, Associate Veterinarian in the Experiment Station. 3 Associate Professor of Entomology, Associate Entomologist in the Experi- ment Station. CALIFORNIA AGRICULTURAL EXTENSION SERVICE [CIRC. 8 Yards. — 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. It is not practicable to treat soil with disinfectants or other chemicals. Para- site eggs may remain alive for years, but most disease germs which Fig. 1. — Chicken-pox; cockerel. Natural infection. 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 1927] DISEASES AND PARASITES OF POULTRY IN CALIFORNIA 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 or moist areas around water troughs especially are to be avoided. Houses. — 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 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 without Fig. 2. — Chicken-pox; baby chick. Natural infection. 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. The floors should be made of concrete or matched flooring, preferably the former. It is very difficult, if not impossible, to efficiently clean and disinfect a dirt floor. To facilitate cleaning, the house should be so arranged that all parts are easily accessible, and nest boxes, feed troughs, etc., should be remov- able. • Isolation of Sick Fowls. — 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 dis- CALIFORNIA AGRICULTURAL EXTENSION SERVICE [ClRC. 8 eases. 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 pro- ducer should be destroyed rather than given treatment. Fig. 3. — Canker; eye, from natural infection with chicken-pox virus. Examination of Dead Fowls.— The presence of most infectious diseases and internal parasites can be best determined by autopsy of a dead fowl. It is a good practice to make an examination of all that die or are killed on account of sickness. By such examination the presence of disease or of parasites many times can be detected before they have made serious progress in 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. 1927] DISEASES AND PARASITES OF POULTRY IN CALIFORNIA Cleaning. — Sanitation is essential for the maintenance of health in any flock. Under this heading is included cleanliness and the appli- cation of disinfectants and parasiticides. Cleanliness is perhaps the most important of the three. By thorough cleaning, many of the disease germs and parasite eggs will be removed. Thorough cleaning involves scrubbing with water after first sweeping and scraping. Cleaning is facilitated by the use of a hot lye solution (1 pound of lye in 40 gallons of water). Droppings of fowls are especially dangerous H^fc .tjifrr % ^^t '^•^B ^f^^^H^*' '**?£ • *jH _ ■ SHI -*^ 5 ' ! ^i%&Sb? ^^ HSHhSKE^^ -,v£; & -' -. '"^^ ~~-^ IHiiUBK**- , igai m : 3$f-' ^««tfdH mE&i - ** it''*'. Sir ***" •-' iaK** ^■f^SmM I .; '■ .^£| " ^i 4v . * I Y (":• f y&S ■ /: Fig. 4. — Chicken-pox and canker of the eye, from natural infection with chicken-pox virus. as a spreader of disease and, therefore, either the dropping boards should be cleaned daily or the roosts constructed so 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. Disinfection. — Disinfectant should be applied only after a thorough cleaning. If applied to a dirty house, it will not penetrate the accumu- lations of filth and little benefit will be derived. Disinfectants are 8 CALIFORNIA AGRICULTURAL EXTENSION SERVICE [ClEC. 8 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 this purpose oily preparations are more effective. A disinfectant of known quality should be selected. One that is dependable and that can be obtained in any locality is Compound Solution of Cresol, containing 50 per cent cresylic acid. There are many such preparations marketed under various trade names. This disinfectant is used in a 3 to 5 per cent solution (1 pint in 3 to 5 gallons of water). The coal tar ''sheep dips" are cheaper and are fairly effective. The "phenol coefficient" which is usually given on the container is an index of the efficiency of such products. The chlorine disinfectants are very efficient germi- cides but are too unstable to be suitable for poultry house disinfection. Preparations sold as crude carbolic acid are variable in their germi- cidal properties and, therefore, are not reliable disinfectants. CHICKEN-POX AND CANKER OR AVIAN DIPHTHERIA Description. — Chicken-pox is manifested by small wart-like growths on the comb, wattles, or skin of the head (figs. 1, 2, 5, and 6), and by the formation of masses of cheesy material or canker in the eyes and the mouth (figs. 3, 4, and 7). Although these last named lesions are entirely different in character from the lesions on the skin they are usually due to the same cause, namely, the virus of chicken-pox. 4 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 are most prevalent during the fall and winter but may occur at any time of the year. 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 almost the entire flock and cause a very great loss, both from decreased egg production and from the death of the infected fowls. The loss will be greater when a large percentage of the infected fowls have canker than when the lesions are largely on the skin. 4 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. 1927 ] DISEASES AND PARASITES OF POULTRY IN CALIFORNIA 9 Control. — Outbreaks of chicken-pox and canker can be controlled by vaccination, in combination with sanitary measures. Vaccination is not advised unless the sanitary measures can be carefully carried out. The use of the chicken-pox vaccine has been very extensive in this state for several years past and the results obtained from vacci- nation have been quite satisfactory. Vaccine should be used on all birds in the flock as soon as the presence of chicken-pox in the flock is noticed. 5 Vaccination of fowls before the appearance of the disease among them is not recommended. The reason for this 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 vaccinate the entire flock upon the appearance of the disease but only the fowls in the pens that are affected. In such cases the vaccine would be used in other pens as soon as the disease appears there. If the vaccine is properly administered it does not have any harmful effect on the general condition of the birds. The egg yield, however, may be 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. Directions for Vaccination. — The materials required for vaccina- tion are : the vaccine ; a syringe ; 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 ; a pan of disinfectant ; and a piece of absorbent cotton for cleansing the skin at the point of injection. 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. Chicken-pox vaccine is administered by injecting it beneath the skin with a hypodermic syringe (fig. 8). The dose is one cubic centi- meter for each fowl. One dose is usually sufficient to check the spread s 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 1% cents per dose. Hypodermic syringes with which to administer the vaccine can also be procured from the University at a cost of $4.00 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. 10 CALIFORNIA AGRICULTURAL EXTENSION SERVICE [ClRC. 8 Figs. 5 and 6. — Chicken-pox; turkey. Natural infection. 1927] DISEASES AND PARASITES OF POULTRY IN CALIFORNIA 11 of the disease in slightly infected flocks. A second treatment given five to seven days later is recommended for all birds in badly infected flocks. A flock may be re-vaccinated whenever the disease continues to spread a month after vaccination. The most convenient place for administer- ing is beneath the skin of the breast under the right thigh. The bird may be held by the person administering the vaccine or by an assist- ant. If the person administering the vaccine holds the bird, the fowl E •'" ■ Wi "*"**-' a 1 jtf > +-\ " 1 -<# J "V V '^I. • ..... % JT ,^m *».ih ' 4m W MM ' * wdk - "'*.» '"'^Im *M% mm mF M\ mm % • m Fig. 7. — Canker of the mouth, turkey; from natural infection with chicken-pox virus. should be laid on the left side with the left wing held back and the right wing, legs and feathers held back with the last three fingers of the left hand. The exposed skin should then be cleansed with a piece of cotton saturated with a good disinfectant, such as a 2 per cent solution of Compound Solution of Cresol (1% tablespoonsful to a quart of boiled water), and picked up with the thumb and forefinger of the left hand. Then with the right hand, the syringe needle should be inserted just beneath the skin and 1 cubic centimeter of vaccine 12 CALIFORNIA AGRICULTURAL EXTENSION SERVICE [ClRC. 8 injected. If an assistant holds the bird, both the wings should be held with the left hand, both legs with the right hand, and the bird placed on a table on its left side with the legs toward the operator. The skin should then be cleansed as directed above and picked up with the thumb and forefinger of the left hand and the hypodermic needle inserted just beneath the skin, being directed toward the head of the bird. Fowls can be vaccinated at the rate of 100 to 400 per hour according to the skill of the operator and the facilities for catching the birds. A syringe of 6 to 10 cubic centimeters capacity is well suited for this work. The needle should be 16 to 18 gauge and from 2 to 2% inches over-all in length. Sanitary precautions. — 1. Although the vaccine is preserved, the amount of preservative is not sufficient to keep it from spoiling if it is exposed to warm tempera- ture for a considerable length of time. Furthermore, vaccine loses its efficiency with age and, therefore, it should be used within three days and never later than seven days after it has been prepared. If old or decomposed vaccine is used, unsatisfactory or bad results will follow. 2. The vaccine should be kept in a cool place on ice if possible, until used, and only one bottle opened at a time. 3. A small, wide-mouthed, covered vessel, such as a %-pint cream bottle or a jelly glass, should be provided as a vaccine container from which to fill the syringe. This should be sterilized by boiling before it is used and afterwards should be kept covered at all times except when the syringe is being filled. It should be well shaken each time the syringe is filled. 4. The syringe should be sterilized by boiling, or by soaking for at least five minutes in a 2-3 per cent solution of a good disinfectant and rinsing with boiling water. 5. The immunizing effect of the vaccine does not take place im- mediately ; therefore, fowls already infected at the time of vaccination or that become infected soon after will develop chicken-pox lesions. Carefully examine each fowl at the time of vaccination and remove from the flock all that are diseased. Most of them will recover if given proper treatment. 6. A week later examine each fowl again and remove from the flock all that have become diseased since vaccination. 7. Do not return a diseased fowl to the healthy flock until the lesions are entirely healed. 1927 ] DISEASES AND PARASITES OF POULTRY IN CALIFORNIA 13 Fig. 8. — Method of holding a fowl and injecting chicken-pox vaccine. Fig. 9. — Method of holding a fowl and removing canker from the mouth. 14 CALIFORNIA AGRICULTURAL EXTENSION SERVICE [CiRC. 8 8. Satisfactory results from vaccination cannot be expected if the diseased fowls are not separated from the healthy. 9- The hypodermic needle should be inserted between the skin and the breast muscle, but not into the breast muscle. Treatment of Sick Fowls. — All diseased birds should be removed from the flock and kept in comfortable quarters where they can be given treatment at two- or four-clay intervals. The scabs which form on the growths on the comb, wattles, or skin should be removed with Fig. 10. — Method of holding a fowl and removing canker from the eyes. a dull knife or a pair of forceps, and tincture of iodine applied to the exposed surface. Collections of cheesy material in the mouth should be removed with forceps (fig. 9) and tincture of iodine applied. Col- lections of cheesy material within the eyelids should be removed by pressing around the eye with the thumb and finger tips (fig. 10) and tincture of iodine applied. If the cheesy material adheres to the eye- ball, it will be necessary to use forceps to remove it. In such cases the eyeball is usually destroyed before the recovery is complete. Tincture of iodine can be applied most conveniently and effectively with a medicine dropper. It will not in any way injure the eyesight or be 1927 J DISEASES AND PARASITES OF POULTRY IN CALIFORNIA 15 otherwise injurious to the birds. The administration of vaccine in addition to local treatment with iodine will hasten recovery and de- crease the loss from death. INFECTIOUS BRONCHITIS Description. — This disease has been variously designated as in- fectious bronchitis, infectious tracheitis, tracheo-laryngitis, chicken "flu," and Canadian "flu." The length of time poultry of this country have suffered from it is not definitely known. Operators and employees of feeding stations claim that it has been present for many years, but losses caused by it have not been serious before the fall of 1924. In some poultry periodicals, the statement is made that it was introduced into this country by show birds from Canada in 1921. The first authentic report of its occurrence in the United States, how- ever, appears to be that of May and Tittsler 6 regarding an outbreak of tracheo-laryngitis in a Rhode Island flock in November, 1923. The first known occurrence of the disease in California was in November, 1924, in a flock of pullets. Since then numerous other outbreaks have occurred in poultry flocks throughout the state. Quite heavy losses were also sustained among fowls in fattening stations. These were chiefly among live fowls shipped from the Middle West (Nebraska), but also to some extent in fowls obtained from California flocks. Losses have been heavier among young birds than among old ones, although fowls of all ages have been affected. It has been noted, however, that the mortality is less and continues over a shorter period in flocks of hens than in flocks of pullets. The predominant symptom of the disease is ' ' gasping for breath. ' ' The affected fowl assumes a sitting position, with the neck drawn in, the beak pointed downward and the eyes closed (fig. 11). At each inhalation, the head is thrown forward and upward, with the beak opened and the intake of air is accompanied by a loud wheezing sound (fig. 12). Spasmodic exhalation or coughing is frequent and often results in the expulsion from the trachea of a mass of clotted blood. Examination may reveal the larynx to be nearly filled with a caseous mass, while in other cases, in the live bird, the cause of the respiratory difficulty is not visible. Collections of mucous or caseous exudate are frequently found within the eyelids. This causes the eyelids to be- come glued together and, in case both eyes are affected, makes it 6 May, H. G., and E. P. Tittsler. Tracheo-laryngitis in poultry. Jour. Amer. Vet. Med. Assn., n.s., 20: 229-231. 1925. 16 CALIFORNIA AGRICULTURAL EXTENSION SERVICE [ClRC. 8 m impossible for the fowl to see. There is usually a discharge from the nostrils. In many cases, this results in the nasal sinuses becoming filled and distended. This condition is indistinguishable from the commonly-occurring roup. The onset of the disease is sudden and the spread through a flock very rapid. An outbreak usually causes a mortality of from 5 to 25 per cent of a flock during a period of from two to four weeks. The disease then disappears about as suddenly as it began. When there is more than one flock on a farm, it may attack one flock after another, but recurrences of the disease in the same flock are uncommon. . ' ; Fig. 11. — An advanced case of infectious bronchitis. Attitude during expiration. The majority of the fowls that die do so within one or two days after symptoms appear. A large percentage of affected fowls that survive the first two days of sickness recover. The cause of the disease is still undetermined. It has been quite definitely proved, however, that the disease is infectious and, there- fore, that it is probably due to some species of bacteria or virus. On autopsy, all organs are apparently normal with the exception of the larynx, the trachea, and the bronchi. The linings of these organs are usually found inflamed and their lumens wholly or par- tially filled with mucus and clotted blood. In some cases, probably those of several days' duration, the mucus in the larynx has become caseated. Occasionally caseous mucus is found extending the entire length of the trachea. In some birds, the amount of clotted blood 1927 ] DISEASES AND PARASITES OF POULTRY IN CALIFORNIA 17 present exceeds that of mucus. The collection of mucus is sometimes confined to the lower portion of the trachea, the upper portion of the trachea and the larynx being entirely free. The degree of inflammation of the mucous membrane varies from slight to an extent such as to impart a bright scarlet color to the membrane. The lungs appear normal except for small areas of congestion. Death in many cases appears to be due entirely to asphyxiation, caused by the filling of the larynx or trachea with caseated mucus or clotted blood. Fig. 12. — Same fowl as fig. 11. Attitude during inspiration. Control and Treatment. — The efforts to control outbreaks of in- fectious bronchitis should be directed toward limiting the spread as much as possible until the outbreak has run its course. It is probable that the rapid spread of the disease is in a large measure due to infection of healthy birds with the mucus and clotted blood expelled from the trachea of affected birds when they cough. A very important control measure, therefore, is the removal of affected birds from the flock before they have begun to cough. The flock should be con- tinuously watched and all birds that exhibit the slightest respiratory difficulty immediately taken out. Other measures are the usual sani- 18 CALIFORNIA AGRICULTURAL EXTENSION SERVICE [ClRC. 8 tary precautions, such as cleaning and disinfection of the houses. A disinfectant, such as potassium permanganate or a chlorine solution, may be added to the drinking water. Spraying the fowls at night with various preparations has been advocated. The apparent benefit obtained from such treatment is probably due to the fact that out- breaks naturally terminate quickly and that a large percentage of affected fowls recover even when no treatment is given. A number of methods for the medicinal treatment of diseased birds have been used. These include chlorine solutions or argyrol, applied in the larynx and trachea; two drops of beechwood creosote in cod- liver oil, given daily; 3-grain doses of quinin sulphate, given three times daily ; 20 minims of aromatic spirits of ammonia, every two hours ; 5 c.c. doses of flavisol, subcutaneously ; 20 to 30 grams of cal- cidin, in hot mash, daily ; and avian mixed bacterins. Definite infor- mation seems to be lacking, however, regarding the actual value of any of these. Removal with forceps or tweezers of masses of caseous mucus or clotted blood that are within reach in the larynx or the upper portion of the trachea is a form of treatment that may save the lives of many birds. COLDS AND ROUP Description. — "Colds" are manifested by a discharge from one or both nostrils. When this discharge collects in the nasal sinuses it causes a marked swelling of the face and is rapidly transformed into a cheesy mass just beneath the eyes. This stage of the disease is called "roup." If fowls did not get "colds," they would not have roup. In turkeys, the material that collects in the nasal sinuses remains a thick, mucilaginous liquid. As a rule, "colds" and roup are confined entirely to the nasal passages, although in many 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, or poor con- dition of the birds rather than to any specific infection. Therefore, the usual cause of a large number in a flock becoming affected at one time is that all of the birds have been exposed to the same unfavorable condition, not because of contact of healthy with diseased birds. It is not likely to seriously affect any flock that is properly housed and cared for. Improper housing conditions are probably the most com- mon cause of colds. Common faults in housing conditions are : pres- ence of cracks in the walls back of the roosts ; poor ventilation ; over- crowding (particularly common in the case of young stock) ; damp- 1927] DISEASES AND PARASITES OF POULTRY IN CALIFORNIA 19 ness, 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. Colds are particularly prevalent in pullets after they have been moved from brooding or rearing houses to laying houses. This is probably the result of the sudden change of environment. It is common for young birds that are infested with intestinal worms to be seriously affected with colds. Fig. 13. — Fowl with roup. Control. — The most important control measure is to determine and, if possible, remove the cause. The houses should be carefully studied for defects and any that are found corrected. Make certain that the number of birds is not too large for the house both during the day and night. When young birds are affected examine some of them for intestinal worms and give the birds proper treatment if any worms are found. Be sure the birds are fed a suitable ration. Keep the houses clean and dry. Treatment. — A satisfactory treatment for individual colds 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 apply- ing 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. It is probably more economical to destroy 20 CALIFORNIA AGRICULTURAL EXTENSION SERVICE [ClRC. 8 birds having roup than to attempt treatment except in the case of birds of unusual value as layers or breeders. Treatment 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. Turkeys with roup do not respond to this treatment. A treatment 7 for turkeys recently recommended consists in reducing the size of the swelling by pressing some of the discharge out through the nostrils and then injecting 1 c.c. (15 drops) of a 15 per cent solution of argyrol with a fine hypodermic needle. The injection is made below and in front of the eye. Great care must be taken not to tear the lining of the nasal passages nor to allow the argyrol to escape into the tissues. 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 x /± lb. Pulverized iron sulphate % lb. Pulverized nux vomica ^ 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 ROUP Description. — 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 (fig. 14); emaciation; a discharge from one or both nostrils which 7 Tyzzer, E. E. The injection of argyrol for the treatment of sinusitis in turkeys. Cornell Vet., 16: 221-224. 1926. 1927] DISEASES AND PARASITES OF POULTRY IN CALIFORNIA 21 Fig. 14. — Typical appearance of fowls with nutritional roup. Fig. 15. — Cheesy material in the eye of a fowl with nutritional roup. 22 CALIFORNIA AGRICULTURAL EXTENSION SERVICE [ClRC. 8 Fig. 16. — An advanced case of nutritional roup, showing the pharynx and esophagus studded with pustules. 1927 ] DISEASES AND PARASITES OF POULTRY IN CALIFORNIA 23 Fig. 17. — Kidneys of a fowl with nutritional roup. 24 CALIFORNIA AGRICULTURAL EXTENSION- SERVICE [ClRC. 8 may be followed by a swelling of the face beneath the eyes; a dis- charge 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 (fig. 15) ; the formation of a yellowish white, round, cheesy pustule-like patches in the mouth and throat of about the size of a pinhead (fig. 16) ; 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 presence of lesions in the eye and mouth, in addition to nasal dis- charge and swelling of the face. Postmortem examination of birds that have died usually shows the kidneys to be very pale and marked with a network of very fine white lines (fig. 17). 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 definitely determined that this disease is due to a deficiency of vitamin A in the ration. Since most of the vitamin A in poultry rations is supplied by green food, nutritional roup usually occurs when there is a shortage of this foodstuff. It may occur even though the birds are fed some 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. Control. — This condition can be readily controlled by supplying the birds with more vitamin A. This is usually accomplished by in- creasing the amount of green food. Yellow carrots, alfalfa leaf and blossom meal, or cod-liver oil may be substituted for greens. The alfalfa leaf and blossom meal and the cod-liver oil are added to the mash in the proportion of 5 pounds and 1 quart respectively in 100 pounds of mash. Very sick birds should be given 1 to 2 c.c. (15-30 drops) cod-liver oil daily. RUPTURED YOLKS Description. — This disease usually occurs among flocks of pullets during the period of heavy production. Occasionally older birds are affected. 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. 1927 ] DISEASES AND PARASITES OF POULTRY IN CALIFORNIA 25 The symptoms of the sick birds are droopiness, diarrhea, dis- coloration 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 enlarged, soft liver which may have minute yellowish white spots; sometimes 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 or fowl typhoid germs can be demonstrated. 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. Control. — This disease appears to be the result of heavy feeding and production, rather than entirely to infection with the fowl cholera or fowl typhoid 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 con- sumed and should also decrease egg production. If the losses have been very heavy the mash 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 simi- lar disinfectant in the drinking water. A one to two-thousand solu- tion of bichloride of mercury is effective and safe. This must be used only in wood, glass, or earthenware vessels and must be kept away from other animals or from children. FOWL CHOLERA Description. — This disease is said to be responsible for severe losses among chickens in some states. In California, however, it appears to be a relatively unimportant cause of chicken mortality. The fowl cholera germ is often found in association with ruptured yolk (see p. 24) but the strains of the organism obtained from such cases are of such low virulence that it is very difficult to produce disease when healthy chickens are inoculated with them. Rather severe outbreaks of the disease in ducks and turkeys do occasionally 26 CALIFORNIA AGRICULTURAL EXTENSION SERVICE [ClEC. 8 take place. In most instances such outbreaks could be attributed as much to the feeding and care the birds had received or to insanitary conditions of the premises as to the fowl cholera germ. Even though the probability of severe losses from this disease may not appear to be great, it is always advisable to send specimens to a bacteriological laboratory for examination whenever sudden death of a few birds in good flesh occurs. This is the only means by which a definite diagnosis can be made. Control. — Fowl cholera is not apt to occur if fowls are provided with sanitary yards, clean, properly constructed houses, and correct rations. If an outbreak should occur, the amount of food should be reduced and sanitary measures, such as cleaning and disinfection of the houses, feed hoppers, drinking vessels, and all other accessories, and the isolation of the sick should be carefully carried out. Reliance cannot be placed upon fowl cholera vaccines or bacterins in preventing or curing this disease. FOWL TYPHOID The occurrence of fowl typhoid in chickens and turkeys is not uncommon in some sections of California. It has been encountered more frequently in general farm flocks than in commercial flocks. The fowl typhoid germ is often found in association with ruptured yolk (see p. 24) but evidence to prove that it is a cause of this con- dition is lacking. Predisposing causes, such as exposure, improper diet, inadequate or insanitary quarters, appear to be necessary for an outbreak of this disease to occur and, therefore, the danger of its occurring in flocks that are properly housed, fed and cared for is not great. The control measures given for fowl cholera apply also to fowl typhoid. The fowl typhoid germ is becoming of greater importance as a cause of disease of young chicks. The manifestations of this disease are identical with those of bacillary white diarrhea and can be dis- tinguished from it only by bacteriological methods. Hens may acquire an infection of the ovaries with the germ and transmit it through eggs to offspring in the same manner as the bacillary white diarrhea germ. The method of prevention and control of fowl typhoid of chicks is the same as for bacillary white diarrhea. The agglutination test for the detection of hens that are carriers of the bacillary white diarrhea germ will also detect carriers of the fowl typhoid germ. 1927 ] DISEASES AND PARASITES OF POULTRY IN CALIFORNIA 27 TUBERCULOSIS Description. — This disease is caused by a specific germ and can- not be produced in any other way. Filthy, damp, crowded houses and yards serve to hasten the spread of the disease through a flock when the infection is present but such conditions are never responsible for the start of the disease. Infected birds exhibit symptoms of infec- tion only in the advanced stages. Then they become emaciated, the comb and shanks are pale and shriveled, and some are lame. Losses from this disease do not often occur in birds less than one year old. wk ^%u€ ' ^^M^fcdJI k^j|^| fe " f ! ^J .:.. JHB ||| - Fig. 18. — Tuberculosis nodules on the intestines and liver of a fowl. 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 (fig. 18). 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 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. Control. — The observance of strict sanitary precautions and the practice of disposing of all fowls over two years old may assist in decreasing loss from the death of infected birds, but will accomplish little in lessening the extent of the infection in a flock. There are two possible methods of eradicating tuberculosis from a flock. The 28 CALIFORNIA AGRICULTURAL EXTENSION SERVICE [CIRC. 8 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 the most practical method to use in small flocks or flocks which are raised solely for egg pro- duction. Fig. 19. — Fowl showing a positive reaction to the tuberculin test. The other method of eradicating tuberculosis is by means of the tuberculin test. This test is made by injecting % 5 to %o cubic centi- meter of substance known as tuberculin into the skin of the wattle. If an injected bird has tuberculosis the wattle will swell (fig. 19). 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. 1927 ] DISEASES AND PARASITES OF POULTRY IN CALIFORNIA 29 COCCIDIOSIS Description. — Coccidiosis is one of the most destructive diseases of young chickens. It is so widespread that, in poultry districts, practically all established poultry farms are infected and new farms quickly become so. The heaviest losses occur in chicks from four to eight weeks old. In infected flocks from 25 to 50 per cent and some- times nearly all of the chicks die in two or three weeks. The large number of unthrifty or "cull" chicks among the survivors in infected flocks that have not been given effective treatment sometimes causes a greater loss to the poultryman than the mortality. Older birds become affected with a slowly fatal (chronic) type of the disease, which may be general in the flock or, as frequently happens, affect only a few birds. The disease frequently occurs in young turkeys as well as in chickens. Coccidiosis is caused by the presence in the intestines of chicks of a microscopic, protozoan parasite called Eimeria avium. 8 The parasite develops and multiplies in the cells of the walls of the intestines. The disease results from the injury to the cells during this period of development. In young chicks, the ceca (blind pouches) are the parts affected, while in older birds with the chronic type of the disease, the small intestines, rather than the ceca, are involved. Severe outbreaks of coccidiosis so frequently occur in flocks which have not received suitable food or care or which are not properly housed, that some poultrymen believe it to be due to such conditions. These conditions do not cause coccidiosis, but render them more susceptible by lowering their natural resistance. 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 chemical treatment of the soil to destroy these parasites has been developed. s Dr. E. E. Tyzzer has recently suggested that there are two species of coccidia in chickens. One species is thought to be non-pathogenic and not to produce hemorrhages, while the other is considered to be pathogenic and the causative organism involved in acute attacks accompanied by the voiding of bloody drop- pings. Observations in California support the idea that two species of coccidia exist but do not permit the conclusion that the one which does not cause hemor- rhage is strictly non-pathogenic. 30 CALIFORNIA AGRICULTURAL EXTENSION SERVICE [ClRC. 8 Attendants may carry infection into brooder houses from con- taminated yards. Chicks may become infected when allowed to run in orchards or gardens that have been fertilized with chicken manure. The infection may be introduced on to new premises by such means as healthy adult fowls which harbor the germs, wild birds, dust-laden wind, visitors, etc. It is improbable that infected hens ever transmit the disease through the egg to their offspring. Usually the first indication of the presence of coccidiosis in a flock of chicks is droopiness of a few. The affected birds remain close to the hover, do not eat, and stand with wings drooping, head drawn in, and eyes closed for long periods of time unless disturbed. This attitude is quite characteristic of the disease (fig. 20). Droopy birds may be seen for two or three days before any deaths occur. The droppings of affected chicks frequently contain blood. The amount varies from that sufficient only to slightly tinge the droppings to enough to give them the appearance of consisting entirely of blood. The bloody droppings usually are seen in the early stages of the out- break. Occasionally they are the first indication of disease observed. Although the presence of blood in the droppings is a frequently occurring and quite characteristic symptom, in many outbreaks of coccidiosis this does not occur. Therefore, "bloody diarrhea," the name for the disease commonly used by poultrymen, does not always apply. The heaviest mortality usually occurs during the first week or ten days after the first droopiness appears. After this, deaths become less frequent but may continue for from three to four weeks. When effective measures of control are not adopted, a large percentage of the survivors fail to develop normally. Such birds may never become profitable and the loss to the poultrymen from this source may be as great as that resulting from mortality. The changes in the organs observed upon examination of dead chicks are usually confined to the ceca. The walls of these organs are, as a rule, thickened. The ceca may be normal in size or markedly distended. They often contain sufficient blood to give them a reddish appearance. The ceca of chicks which linger for a week or more before death often contain an accumulation of grayish or yellowish- white, cheesy material (fig. 21). Frequently chicks which have died of coccidiosis exhibit no definite marked change in the appearance of the ceca or of the cecal contents. In such cases, the disease can be recognized only by the finding of oocysts on microscopic examination of the contents of the ceca. 1927 ] DISEASES AND PARASITES OF POULTRY IN CALIFORNIA 31 Fig. 20.— Chick with coccidiosis. » * i I m ~ * ■ Fig. 21. — Ceca of chick with coccidiosis. 32 CALIFORNIA AGRICULTURAL EXTENSION SERVICE [ClRC. 8 Occasionally the liver is involved. The liver lesions, when present, consist of small, white or yellowish specks on the surface. The chronic type of the disease is seen in older birds, usually pullets between the ages of four and eight months. It develops slowly and may affect only a few fowls in a flock. The prominent symptoms are loss of appetite, roughened, dirty plumage, gradual loss of flesh, paleness of the comb and wattles, leg weakness or "paralysis" of the legs, or sluggish, weak movements when walking. In extreme cases of leg weakness, the fowl may lie on its side with both legs extended backward (fig. 22), or it may lie on its breast with one leg extended forward and the other backward (fig. 23). Some pullets that are unable to stand appear quite normal in a sitting posture. Fig. 22. — Seven-months-old pullet with chronic coccidiosis. Death from chronic infection occurs only after several days or even weeks of sickness. Chronic coccidiosis may be easily confused with the symptoms resulting from external parasites, intestinal worms or nutritional disturbances. In pullets with the chronic type of the disease, the lesions are confined to the small intestines. The intestinal walls become thickened and the lining has a spongy appearance. In severe cases, red blotches or hemorrhagic areas may be present. Occasionally there is a slough- ing of patches of the lining. The ceca rarely show any change. Chronic coccidiosis can be differentiated from the effects on chickens of certain species of intestinal worms or from some nutri- tional disturbances only by microscopic examination of intestinal con- tents or of scrapings from the lining of the intestines of affected fowls. 192 7 ] DISEASES AND PARASITES OF POULTRY IN CALIFORNIA 33 Frequently both coccidial parasites and one or more species of intes- tinal worms may be present in the same fowl. Therefore, before an intelligent decision can be made as to the treatment of fowls suspected of having chronic coccidiosis, it must be determined: first, whether coccidial parasites are present ; second, whether other intestinal para- sites are present; and third, whether there is any relation between nutrition and the condition of the fowls. Control. — Outbreaks of coccidiosis can usually be promptly con- trolled by feeding sufficient dry or liquid skim-milk or buttermilk and by maintaining proper sanitation in the brooder houses and yards. If the sanitary measures are neglected little benefit from milk feeding can be expected. Fig. 23. — Four-months-old pullet with chronic coccidiosis. If dry milk is used it should constitute 40 per cent of the mash. The composition of the mash is not of importance as long as it con- tains 40 per cent of dry milk and makes a suitable mixture for feeding to young chickens. A mixture that has been found satisfactory con- sists of the following ingredients : Dry skim-milk or buttermilk 40 pounds Wheat bran 10 pounds Yellow cornmeal 30 pounds Ground barley 20 pounds Start feeding the mash as soon as the presence of the disease is determined. Keep the mash constantly before the chicks in hoppers or troughs constructed so as to prevent waste. 34 CALIFORNIA AGRICULTURAL EXTENSION SERVICE [ClRC. 8 Feed grain once or twice daily but restrict the amount to from one-third to one-half the weight of mash consumed. If more grain is fed, mash consumption will be reduced and less satisfactory results will be obtained. Continue this system of mash and grain feeding as long as there is any indication of the disease. This usually requires from one to two weeks. If desired, the ration can then be very grad- ually changed to the one in use before coccidiosis started. Do not start the change in the ration too soon nor make it too abruptly. Feed greens as usual. If the supply of greens is insufficient, add one quart of cod-liver oil to each one hundred pounds of mash. This is also advisable when weather conditions or weakness of chicks prevents them from running outside. Chicks that are run on contaminated soil are less liable to become fatally infected with coccidiosis if they are fed according to this method from the fourth to the eighth week. Feeding mash containing 40 per cent dry milk for a longer period is not recommended. When liquid vnilk, such as buttermilk or skim-milk, is to be used, it should be of good quality. Keep the milk constantly before the chicks in fountains or troughs. If troughs are used, provide covers that will prevent the chicks from walking in them or roosting over them. Provide sufficient containers so that all the chicks can drink freely and the weaker chicks will not be crowded away. Allow the chicks no water. Feed no mash. Feed grain twice daily, very spar- ingly in the morning and a larger amount at night. Feed greens as usual. Add one quart of cod-liver oil to each one hundred pounds of mash if the supply of greens is insufficient or the chicks cannot go out of doors. After all evidence of the disease has disappeared, the feeding of mash may be very gradually resumed, water again given, and the amount of milk reduced. Do not start this change in feeding too soon nor complete it too rapidly. A condensed milk product, such as semi-solid buttermilk, after dilution, may be used in the same manner as buttermilk. Use one part to two or three parts of water. Greater dilutions are less beneficial. Many poultrymen report satisfactory results from the use of undiluted semi-solid buttermilk. If it is fed in this way, water must be supplied. The sanitary measures recommended are designed to prevent the spread of the germs from the diseased chicks and to provide con- ditions favorable to maintaining good health so that the natural resistance of the chicks to disease will not be lowered. When coccidiosis appears, thoroughly clean the brooder houses or move the chicks to other brooders that have been cleaned and disin- 192 7 J DISEASES AND PARASITES OF POULTRY IN CALIFORNIA 35 fected. Cover the floor with litter. Clean the houses and put in fresh litter daily. When chicks are fed liberally with milk, either dry or liquid, the droppings become watery and are voided frequently. This, in itself, is not harmful. The watery consistency of the droppings, however, causes the litter and floor to become wet in a short time. This makes it necessary to clean out the houses and renew the litter daily in order to keep the floor dry. The daily cleaning also removes from the houses a large percentage of the coccidial parasites present in the droppings from infected chicks. Divide the chicks into as many flocks as the number of brooders available will permit. When the flocks are small, it is easier to keep the houses clean and dry. Be sure that the brooder houses are kept warm enough and are well ventilated. Warmth and fresh air are essential for the health of the chicks and also assist in keeping the houses dry. Separate the visibly sick chicks from those apparently healthy as soon as the disease appears. Kill the worst cases. Burn the dead. Watch the healthy chicks carefully so that those that later become sick can be promptly detected and removed. Contamination of the soil with coccidiosis germs is greatest in that part of the yards adjacent to the houses where the chicks spend most of their time when outside. The surface of this part of the yard should be scraped or swept and the sweepings removed. The entire yard should be plowed as deeply as possible. Corners and other places that cannot be reached by the plow should be spaded. In experimental trials to determine the value of hydrochloric acid, catechu, a mixture of bichloride of mercury and sulphocarbolates (coccidiosis powder), potassium dichromate, powdered ipecac, and bismuth subnitrate, for combating coccidiosis, none of these drugs were found to be effective. BACILLARY WHITE DIARRHEA OF CHICKS Description. — Bacillary white diarrhea is a highly contagious disease of young chicks, caused by infection with a specific germ known as Bacterium pullorum. The infection also occurs in adults, but is seldom recognized since it is localized in the ovaries (fig. 24) and usually pro- duces no visible symptoms. However, the disease in adults, breeding stock in particular, presents a serious problem because some of the eggs laid by such fowls carry the infection and transmit it directly to chicks hatched from them. Infection from this source is the most common cause of the start of outbreaks among chicks. Outbreaks may also start from infection picked up by chicks that are hatched 36 CALIFORNIA AGRICULTURAL EXTENSION SERVICE [ClEC. 8 in contaminated incubators or reared in contaminated brooders or pens. The droppings of infected chicks contain large numbers of the germs and are the means of rapidly spreading the disease through a flock. The disease usually appears within three days after the chicks are hatched. The mortality is usually high, the average probably being more than 50 per cent. Losses are greatest during the first two weeks but may continue for three or four weeks. In the acute type of the disease the chicks become drowsy, their wings droop, they sway back and forth when in a standing position and move with an unsteady gait and many of them die within a few hours. There is often a deposit of chalk-like material on the feathers around the vent. In cases of long duration, the accumulation may reach sufficient size to block up the vent. Chicks that survive for a longer period appear weak, dull, fail to grow, and have a tendency to the development of a large abdomen. Mildly infected chicks grow to maturity and, while they appear to be healthy, harbor the infection in the ovaries and become carriers of it. The liver of dead chicks is usually either a uniform yellowish- brown color or yellowish-brown streaked with red. Unabsorbed yolk is nearly always present in the abdominal cavity. The yolk may be nearly full size, liquid in consistency, and yellowish-brown in color or smaller in size and gelatinous or cheesy, according to the length of time the chick may have lived. Changes in the other organs are difficult to detect. Disease in young chicks manifested by symptoms and lesions identical with those due to infection with Bacterium pullorum fre- quently results from "common" causes such as improper incubation, overheating, chilling, improper feeding and housing or any other brooding error that may lower the vitality of the chicks. The only means of distinguishing bacillary white diarrhea from disease due to a non-infectious cause is by bacteriologic examination. Owners of flocks in which losses suspected to be due to bacillary white diarrhea occur should submit specimens for examination to the laboratories of the Division of Veterinary Science, University of California. Prevention and Control. — Bacillary white diarrhea is such a de- structive disease that every precaution should be taken to prevent its occurrence. The danger of chicks becoming infected from contaminated incubators and brooders can be overcome by always cleaning and disinfecting incubators before eggs are set and brooders (including 1927 ] DISEASES AND PARASITES OF POULTRY IN CALIFORNIA 37 troughs, fountains and other accessories) before chicks are placed in them. Many of the chicks that hatch from infected eggs are under- sized or weak. Therefore the practice of destroying all "cull" chicks as soon as they hatch would, in some instances at least, assist in pre- venting a serious outbreak. Fig. 24. — Ovaries of a hen infected with the bacillary white diarrhea germ. Numbers 1 and 2 are normal yolks. Numbers 3 to 9 and many of the smaller yolks are abnormal because of the infection. The mature hen as a source of the infection in chicks may be avoided by securing eggs, chicks and breeding stock only from flocks that are free from infection with the bacillary white diarrhea germ. 38 CALIFORNIA AGRICULTURAL EXTENSION SERVICE [ClRC. 8 Figs. 25 and 26. — Securing blood for agglutination test for bacillary white diarrhea infection in breeding stock. 1927] DISEASES AND PARASITES OF POULTRY IN CALIFORNIA 39 Many infected hens can be eliminated by careful culling of flocks and using for breeding purposes only the highest producing hens. The only definite means of detecting infected hens, however, is a blood test, known as an agglutination test (figs. 25 and 26). A single test will not detect all birds in a flock that are infected, but when a flock is tested annually, or more frequently, and only birds that pass the test are used for breeding, the danger of losses from bacillary white diarrhea among offspring from the flock will be minimized. Detailed information regarding the test may be obtained from the Division of Veterinary Science, University of California, Berkeley. There are no specific measures to be used in combating outbreaks. Sanitary precautions, such as the prompt removal and destruction of all sick and dead chicks, dividing the flock into small units, and moving the chicks into cleaned and disinfected pens, will assist in reducing the mortality. Drugs have been found to be of little benefit. Recent experiments at the Rhode Island .Agricultural Experiment Station, however, indicate that replacing the drinking water with a dilute solution of a chlorine disinfectant may help to decrease mor- tality. Fig. 27. — These birds were raised together in a well lighted house and fed the same ration. The one on the left was placed in a box outside in the sunshine for about an hour each day. The one on the right received sunlight only through a glass window. This is a pronounced case of leg weakness due entirely to lack of exposure to direct sunlight. 40 CALIFORNIA AGRICULTURAL EXTENSION SERVICE [ClRC. 8 LEG WEAKNESS OF CHICKS Leg weakness is of common occurrence among chicks and for many years was thought to be due to improper diet and confinement in houses. It is now known that the trouble results when chicks do not get sufficient exposure to direct sunlight (fig. 27). A deficiency of minerals in the ration may also cause leg weakness, but the common cause is a deficiency of direct sunlight. It has been generally known that flocks in which leg weakness occurred were benefited by being allowed to run outside. The benefit is due to exposture to the sunlight, not to the chicks getting on the ground as was commonly supposed. Leg weakness is apt to occur whenever there is a long period of cloudy or rainy weather during the brooding season. Relief is obtained by making certain that the chicks get one or two hours of exposure to direct sunlight every day. Sunlight that passes through an ordinary glass window is of no benefit. Cod-liver oil possesses the same property of preventing and curing leg weakness as sunlight. It is usually easier to give cod-liver oil than to see that all chicks get sufficient exposure to sunlight. Feeding mash containing 1 quart of cod-liver oil to each 100 pounds to an affected flock will quickly stop the occurrence of leg weakness. Feeding such a mixture throughout the brooding season will entirely prevent the trouble. BLACKHEAD IN TURKEYS Description. — Blackhead has long been known to occur in Cali- fornia, and is undoubtedly responsible for severe losses. Observations made in some sections indicate that the disease has not been prevalent to any great extent in flocks that are run on well drained unirrigated ranges and grain fields. It is believed that blackhead as a serious disease will be found to be localized to a considerable degree in those sections where the land is low, wet or under irrigation, or on land on which chickens or turkeys are raised in confinement year after year. There are two factors involved in the production of the disease, one the blackhead parasite, a microscopic organism which enters the tissues and produces the characteristic changes, and the other the cecum worm (see p. 60) which presumably opens up a way for the blackhead parasite to enter. It is possible that there are other factors that may take the place of the cecum worm in the production of black- head, but none have been found. Turkeys become infected when they are run on soil contaminated with the blackhead parasites and the cecum worm eggs. 1927] DISEASES AND PARASITES OF POULTRY IN CALIFORNIA 41 r V