Bacteria associated with beak necrosis in broiler breeder hens

Beak necrosis occurred in 48 per cent of female broiler breeders used fro nutritional studies but none was found in male broiler breeders or in either sex of single comb white Leghorns. About 10 per cent mortality, probably largely due to beak necroses, occurred in the affected flock. Based on electron microscopic photographs of affected beak tissue, we suggest that in our study the breakdown of beaks was associated with the presence of a single morphological type of Gram-positive bacterium.