During attempts to determine the riboflavin requirement of poults, in which both simplified and commercial type rations were used, dermatitis occurred regardless of the riboflavin intake. Jukes1 reported that riboflavin prevented dermatitis in poults. Recently, Hegsted, et al.,2 reported a dermatitis in chicks distinct from pantothenic acid deficiency and apparently unrelated to riboflavin. Since the dermatitis observed by us in turkeys appeared to be similar to that described by Hegsted, et al., the essential role of biotin in turkey nutrition was investigated.The basal ration had the following percentage composition: corn starch, 32.8; purified casein, 30; purified wheat bran, 20; polished rice, 5; soybean oil, 5; cod liver oil (400 D), 1; wheat germ oil, 2; mineral mixture, 4; choline, 0.2; thiamin, 0.0005. and pyridoxin, 0.0005. Day-old Bronze turkey poults were used throughout the experiment. They were kept in electrically heated brooders, equipped with hardware cloth floors. The experimental ration ...