Vitamin B12 Requirements of Hens as Affected by Choline and Penicillin ,

THE discovery and availability of vitamin B12 in crystalline form has made it possible to study the hen’s requirements for this vitamin. Pertinent literature regarding the ability of vitamin B12 to promote hatchability of eggs laid by hens fed vegetable diets has been reviewed by Berg, Bearse, McGinnis and McClary (1952). These studies were initiated in December, 1948 and were continued through August, 1951. New Hampshire hens reared to maturity on a practical ration under range conditions and progeny of these hens were used. The chicks were kept in back-warmer type battery brooders under the usual management conditions with ad libitum feeding. Fertility was obtained by natural matings and all eggs were candled on the eighteenth day of incubation to determine percent fertility. The basal diet used during the second and third year of experimental work is presented in Table 1. The diet fed during the first laying season …