966 Scabies. 



^ion is the first to be attacked. On the affected parts of the 

 body, falling ont of the feathers is noticeable, often also they 

 break off at the level of or close to the snrface of the skin; 

 the large feathers of the tail and wings are not involved. The 

 stumps" of feathers remaining in the feathered bulbs become 

 cleft and fine scales form on the skin. At the periphery of the l)ald 

 patch the quills of drawn out feathers are covered with epider- 

 mis scales in which the mites are demonstrable. The skin itself 

 is elastic, pale red and not noticeably thickened ; at times, how- 

 ever, one finds it inflamed and dotted with nodular formations. 

 In such cases the hens lay fewer eggs, emaciation sets in, and 



Fig. 151. Scab caused bij Knemidocoptes Iccvis on the neck and head of a cock, with 

 favns on the comb. 



now and then the birds become cachectic and die. Cocks are 

 attacked more severely as a rule. 



The falling out of the feathers due to Knemidocoptes kevis has, according to 

 Neumann, frequently been mistaken for abnormal moulting. According to the same 

 author most cases of feather picking are caused by the Knemidocoptes tevis. 



Mange of the feathered parts of the body occurs now and 

 then in conjunction with foot mange, and leads in such cases to 

 the supposition that scab of the feathered area may be due to 

 Knemidocoptes mutans. A mistake is quite easily possible 



