Zinc Requirement for Normal Feathering of Commercial Leghorn-Type Pullets

Commercial egg type chicks have been fed practical type starting rations containing 5 percent meat scrap and 5 percent fish meal. The basal diet analyzed 38–44 p.p.m. zinc for the different years. The use of a new feed mill increased the level in the basal diet to 52–55 p.p.m. Addition of zinc carbonate decreased the incidence of a feather abnormality from 5–20 percent down to very low levels. Total zinc levels of 52 p.p.m. for 3 weeks did not prevent the fraying. However, 78 p.p.m. and higher levels for only the first week gave good protection. Feeding the higher levels of zinc for only the first week of life gave excellent protection. Weight gains were not improved significantly by zinc additions. A feather condition described as a blister appeared in frequencies of .4–2.2% even with commercial egg strains.