In chickens, rose comb (R) is dominant to single comb (r). A homozygous rose-combed rooster is mated with a single-combed hen. All of the chicks in the F1 generation were kept together as a group for several years. They were allowed to mate only within their own group. What is the expected phenotype of the F2 chicks?
a.100% rose comb
b.75% rose comb and 25% single comb
c.100% single comb
d.50% rose comb and 50% single comb