356.. Knemidokoptosis, known also as scaly or chalky legs, is characterized by the appearance of extensive, rough and hard crusts on the featherless part of the legs. Adult birds are generally affected (hens, turkeys, pheasants, exotic birds). It is caused by Knemidokoptes mutans. The lesions are secondary to an inflammatory reaction, in which the thickening of the cutaneous epidermis together with released exudate forms the crusts on legs. The infection occurs by contact between birds. The control is done by isolation of affected birds, leg bathing with warm acaricide solution and warm vegetable oil that helps the decrustation.