530 



A STUDY OF FARM ANIMALS 



that eggs for hatching come from a flock free from this 

 malady. The disease may be detected by a blood test of 

 egg-laying hens, and such tests are made by some of the state 

 experiment stations. Proper sanitation of the incubator and 

 chicken quarters is vitally necessary. The incubator should 

 be kept in the dark until the chicks are removed to the 

 brooder, thus in a measure preventing the chicks from pick- 

 ing bits from the eggs. It is also wise to keep the chicks in 

 small lots, thus restricting spread of the disease. Sour milk 

 is highly recommended as a preventive of the disease. 



Tuberculosis of fowls, or what is known as avian tuber- 

 culosis, has been 

 known in the 

 United States since 

 1899, it being first 

 reported in investi- 

 gations at the 

 Oregon Experiment 

 Station. Since then 

 it has been located 

 in different parts 

 of the country, and 

 the disease seems to 

 be becoming quite 

 common. Tuber- 

 culosis of fowls is 

 much the same as 

 that of humans, 

 cattle, or swine, and 

 affects the birds in 

 like manner. There is emaciation, paleness of comb, wattles, 

 and skin, oftentimes a persistent greenish diarrhea, lameness, 

 and in the later stages the feathers become dry and ruffled, 

 and the bird is weak and stands about, moving but little. A 

 post mortem examination shows the liver more or less thickly 



Figure 258. — The spleen (A) and liver (B) of a tuber- 

 cular fowl. The white spots are nodules, or tuber- 

 cles. Photograph from Ohio State University. 



