Effect of feathering alleles (K/k+) on laying performance, hatchability parameters and some body measurements in two lines of white plymouth rock hens

The study aimed to investigate the effects of sex - linked feathering alleles on laying performance, hatchability parameters and body measurements in hens from two White Plymouth Rock lines (line L and line K) used as maternal lines in broiler production. Four groups of 18-week-old hens were formed, two of each line, with genotype K/W (slow feathering) and k+/W (rapid feathering) respectively. Groups of line L included 72 hens divided into 6 boxes with 1 rooster per 12 hens, whereas line K groups comprised 96 hens of each genotype, housed in 8 boxes with one rooster per 12 hens, totally 192 birds. The K locus alleles had no significant effect on egg production traits (p>0.05). The presence of slow feathering allele resulted in lower fertility and hatchability of set eggs in both studied lines (p<0.05). A substantial effect of feathering rate alleles was observed with respect to the egg shape index (p<0.05), eggshell thickness (p<0.001) and albumen index (p<0.05). The presence of the slow feathering allele resulted in lower live body weight of birds from line K at the age of 36 weeks (p<0.05), but in longer thighs (p<0.01) and metatarsi (p<0.001) in both lines. The selection for creation of slow feathering lines for feather sexing purposes should take into consideration the effect of the K gene on studied traits.