Sex-linked feathering alleles (K, k+) in chickens of diverse genetic backgrounds

Chicks were produced for this experiment by mating males from a broiler parent stock that were heterozygous (K/k+) at the sex-linked feathering locus with early feathering (fc+/w) females. Dams were from three diverse lines - White Plymouth Rocks selected for high or low 8-week, body weight and White Leghorns selected for high antibody response to sheep erythrocytes. Escherichia coli (E. coli) were injected into the caudal air sac of some chickens and others were maintained as uninoculated controls. Body weights were obtained immediately before inoculation and at subsequent 24-hour periods until 5 days after inoculation, at which time air sac and heart lesions were scored. Chicks were less affected by E. coli if they were maintained in warmer environments, younger at time of inoculation, or from the low weight dam line. Lesion scores suggested that chicks with only allele fc+ were slightly more resistant to E. coli inoculation than those with the K allele.