DISEASES AND PARASITES OF FOWLS 393 



of thousands of these bloodthirsty villains are plying their 

 trade, the hen will soon be pumped dry of blood. Others 

 do not suck the blood but irritate the fowl beyond endur- 

 ance by moving about or running foot races, possibly with 

 10,000 other entrants, on the skin. Others burrow into 

 the skin or flesh ; others suck the liquid contents from the 

 cells of the skin and exude a poison under the skin. Still 

 others do their damage by carrying infectious diseases from 

 one fowl to another. 



The internal parasites affect the wind-pipe, the stomach 

 and intestines and cause various derangements. 



Poultry parasites are divided, therefore, into two classes, 

 external and internal. 



External parasites may be divided into two kinds, namely, 

 mites and insects. 



Mites. The chicken mite (Dermanyssus gallinea) causes 

 more loss to the poultryman than any other species of mite 

 and probably more than any other kind of insect or louse. 

 These mites breed on the under side of the roost porches, 

 especially where there is a rough surface and small cracks 

 or crevices. They also breed in the cracks of the walls near 

 the perches and in the nest boxes. Their presence will 

 often be indicated by white dust-like patches on the 

 walls. They are not found in any numbers on the fowl 

 during the day but they crowd out of their hiding-places 

 onto the fowls at night and suck the blood, then go back 

 to their hiding. During the warm days of spring and sum- 

 mer they multiply rapidly. 



Frequently sitting hens die en the nest, being literally 

 bled to death by the pests. Sometimes they multiply so 

 rapidly that they can be gathered by handfuls in nests or 

 other places where they are undisturbed, especially under 

 sitting hens. They live several weeks after being filled with 

 blood. Under certain conditions they have been known 



