In chickens, the white feathered allele is dominant to colored, feathered legs are dominant to non-feathered (clean), and "pea comb" is dominant to single comb. Each pair of alleles segregate independently. If a true-breeding white, feathered, pea comb rooster is crossed with a colored, non-feathered, single comb hen, and the F1 is allowed to interbreed, what proportion of the birds in the F2 will produce only white, feathered, pea comb progeny if crossed to colored, clean, single-combed chickens?