Evidence for a High Zinc Requirement at the Onset of Egg Production

IN PREVIOUS studies at this station, Berg et al. (1962), it was observed that the incidence of an abnormal wing feather condition increased among chicks hatched from eggs laid by breeder pullets just entering production, as level of calcium in the maternal diet was increased. The abnormal wing feather condition, which was similar to that described by Young et al. (1958) as a symptom of zinc deficiency, was markedly decreased in chicks hatched from eggs laid four weeks after the pullets had reached 30 percent lay. Symptoms of zinc deficiency in the chicks were evident even though the chick diet calculated to contain 38 p.p.m.2 of zinc and the chicks were kept in galvanized metal batteries. This paper will present further evidence as to the effect of calcium level of the breeder diet on abnormal wing feather development of chicks, and evidence for an abnormally high zinc requirement at the…