Genetics are complex with many things at play.. This quote taken from the link that follows it..
"Feathered legs:
Pti-1, Pti-2, Pti-1B, Pti-1L - Dominant. Two different feathered leg loci with perhaps four alleles for the Pti-1 locus (Pti-1, Pti-1B, Pti-1L and pti-1+ : one should always assume...