DISEASES OF POULTRY. 173 



convenience to the^ birds which they infest. Some 

 live between the barbules of the feathers, others live 

 within the quills, and these are sometimes called 

 feather mites. The Cheyletus lives at the base of the 

 feathers. The Syringophilus lives within the quills 

 of the tail, the wing, and the wing- -coverts. The 

 quills of the affected feathers lose their transparency 

 and are filled with an opaque powder, which, upon 

 microscopical examination, is found to consist of the 

 parasites, their excreta, the skins which they have 

 shed and the debris of the interior of the quill. It is 

 supposed that this alteration of the feather has no 

 effect upon the health of the bird. The Dermoglyphus 

 and Pterolichus also live within the quills. 



Symptoms. — Small chickens do not thrive, and if 

 badly infested they droop and die. The larger chick- 

 ens and grown birds, when severely tormented by ex- 

 ternal parasites, lose flesh, the skin and comb become 

 pale and bloodless ; the birds are scratching, picking 

 and dusting themselves continually. Unable to rest 

 either day or night, and losing comparatively large 

 quantities of blood, the birds rapidly become emaci- 

 ated, sitting hens forsake their nests, the feathers be- 

 come broken and drop out, and the skin becomes 

 abraded and sore. The fowls no longer thrive, egg 

 production is greatly diminished or arrested, and oc- 

 casionally a bird is found dead. 



By opening the feathers carefully about the head, 

 neck, under the wings, or about the vent of the fowls, 

 lice may be seen moving about. Persons going about 

 the roosting -places are covered with the vermin, and 

 an examination of the roosts and crevices of the 

 building near the roosts will reveal large clusters of 



