Some phenotypic feathering characteristics of chicks with dominant sex-linked late feathering gene (K) in white leghorn

This experiment was carried out to investigate the phenotypic feathering characteristics in White Leghorn chicks specified feathering genotype by the genetic analysis of the dominant sex-linked late feathering gene (K). After hatching, the shape of the wing feather was observed, and the lengths of the wing and tail feathers were measured. In addition, it was attempted to estimate the determination of late feathering genotype (homozygous (K/K) or heterozygous (K/ksup(+))) on the basis of these phenotypic informations in male chicks. The following conclusions were obtained ; In female chicks, the point of the secondary feathers in K/- was thin shape compared in ksup(+)/-. The differences between the length of the number 2 primary feather and the number 2 secondary feather within K/ - and ksup(+)/- were significant. The length of the tail feather was significantly shorter in the K/- females than in the ksup(+)/- females up to the age of 10 weeks. When K/K and K/ksup(+) male chicks were compared, the point of the secondary wing feathers was further thin in the K/K males than in the K/sup(+) male. Especially, the point of secondary wing feathers in the K/K males was linear shape. The differences of the length of the number 2 primary feather and the number 2 secondary feathers in K/K, were shorter than in K/sup(+) up to the age of 6 weeks significantly. Furthermore, highly significant difference existed between K/K and K/ksup(+) males in the length of tail feather at 2 weeks of age. Therefore, these phenotypic characteristics in male chicks, the length of the tail feathers at 2 weeks of age and the point of the secondary feathers at 4 weeks of age, were able to distinguish homozygous (K/K) and heterozygous (K/ksup(+)) genotype. These results indicate that the form of the secondary feather and the length of the tail feather become effective indices to estimate the determination of late feathering genotypes in males.