DISEASES OF POUI.TKV. 



205 





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The birds occasionally peck at or scratch the affected 

 parts with the beak. They do this most frequently 

 at night and in warm weather. 



Causation.- Scaly legs is a form of scabies or 

 mange caused by the mite known as the Sarcoptcs 

 mutans. It ,s a strictly contagious disease although 

 It does not spread rapidly from bird to bird, and there 

 may be only a few noticeably affected birds in a flock. 

 The Asiatic breeds are most 

 susceptible to it, and many 

 birds, even of these breeds, 

 resist the attacks of the mites, 

 and never show anysymptoms. 

 It attacks quite a variety of 

 birds— fowls, turkeys, pheas- 

 ants, partridges and cage 

 birds, but has not been ob- 

 served in ducks and geese. In 

 the production of scaly legs, 



the .S'rt';w/to;«///rt';/i penetrates Tr„ -« . 



beneath the epidermic scaIp'; a ^P^'^^ ovitrerous female; 



"^'^^ dorsal surface; mag-iiified 100 



on the upper surface of the '^'^'"^t^"- 

 foot and the front of the shank, and by burrowing there 

 sets up an irritation which leads to a multiplication of 

 the cells of the part, and an exudation of serum It 

 IS by the union of these two products that the white, 

 powdery crust is formed, which raises the epidermic 

 scales from their normal position. If the crusts are 

 removed and the under surface examined with a lens 

 they are found to contain a large number of depres- 

 sionsineachof which a female, egg-containing Sar- 

 copt is lodged. The larvae, males and younger females 

 are found wandering beneath tlie crusts. The crust 

 contains so many cavities that it has very much the 



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