tail feather growth rate.

[slschul3]

Hope someone can answer this question. I hatched a bunch of red star chicks from a red star father and red star mother. I know they cannot be sexed by there feathering visuals anymore but about half of the chicks at one month have tail feathers and the other half do not. I,m guessing that the ones with tail feathers have the dominant K gene and are fast feathering? Would it be correct to assume that if one of those fast feather turned out to be a rooster could i bree

d him to another slow feathering hen and get a feather sex link?