8 
THE COLORADO EXPERIMENT STATION 
right indicates the natural size. 
Figure 7.— Upeurus baculus, from the pigeon. Letters indicate same parts as 
in Fig. 6. 
Figure 8.— Sarcoptes limtaiis, variety gallinae, the scab parasite producing 
scaly legs in the hen. a, the mouth parts with which it wounds the skin and 
causes serum to exude; b, the short legs; c, the small dot indicates its natural size. 
MITES 
Scaly Legs (Scabies) 
This disease is caused by a parasite (Sarcoptes mutans variety gallinae), 
which belongs to the same family as the scab parasite of cattle, horses, sheep, 
hogs, cats and dogs. The parasite is often called a mite, owing to its small 
size. In Fig. 8 its size is indicated by a small mark, to the right of the draw¬ 
ing of the parasite, which is magnified 100 times. In the drawing, note the 
short, strong, stubby legs, and the mouth parts arranged for biting. 
CONDITION PRODUCED.—This parasite attacks chickens, turkeys, and 
cage birds, but the writer has not observed it on geese and ducks. It attacks 
the unfeathered portion of the leg above the foot and often the top portion of 
the toes. The minute parasite crawls under the scale of the legs and there 
irritates the tissue, for the purpose of obtaining food with the mouth parts 
as pictured in the drawing referred to above. As a result of this irritation, 
a vesicle or small blister appears. The blister, practically microscopic in size, 
after a time ruptures, the serum dries, and makes a minute scale. As the 
parasites become more numerous, by continually irritating the parts, they 
cause a piling up of scab and the leg presents an appearance like Fig. 9. The 
parasites can be found as minute white specks in the serum between the scab 
and leg. Both legs are usually affected at the same time. Itching is present 
and the birds may be noted to pick at the parts. Itching is more intense at 
night. The bird may become weak, stop laying and even may die. 
LIFE HISTORY.—The female mite lays her eggs under the scabs where, 
in about ten days, if conditions are favorable, they hatch. The larvae (young 
mites) now moult several times and finally arrive at the mature stage. 
The tearing off of scabby patches favors the escape of the parasite, and 
other birds become infested by being placed in quarters occupied by infested 
birds, or by introducing an infested one into the flock. 
TREATMENT.—Soak the scabby patches with soapy water and the 
