Dominant white is the Only gene that can mask sex link barring but only on Birchen(ER) or Extended black(E) allele background, wich is what barred rock hens are so thats a moot point, the headspot is not visible on homozygous wheaten chicks eWh/eWh
you can only use a barred rock hen and a black/colored rooster... the boys have a white spot on their head the girls will lack this spot, both will have black chick down