Malformation of the Tarso-Metatarsal and Phalangeal Bones of Chicks

Abstract

DURING the past 10 years the occurrence of a deformity of the feet of chicks, called “crooked toes” by poultrymen, has been observed with increasing frequency on poultry farms. In this deformity the toes curl inwardly in most instances but occasionally outward curling of the toes has been observed. Illustrations of the deformity are given in Figure 1. Upon dissection of the tarso-metatarsi and the phalanges it was found that the deformity was caused by a malformation of these bones. The distal end of the tarsometatarsus becomes bent and rotates laterally and the proximal phalanges become twisted with resultant loss of use of the toes. Illustrations of normal and malformed bones are given in Figure 2.The crooked-toe deformity was observed by Norris, Heuser, and Wilgus (1929-1930) in connection with the discovery of nutritional leg paralysis in chicks. Field cases of the deformity were found in White Leghorn chicks by .