Recessive white requires two copies of the gene, one from each parent. Your rooster and at least one of your hens are considered 'split' for white. They carry one gene, not two, so they do not express the white. If you breed her back to her father, then you'll get 50% whites, and 50% splits. Breeding her to an unrelated male will produce 100% spilt for white chicks, and will give you some more genetic diversity to work with.
Mine came from a black roo. If my almost 5 wk old white is a roo, that will make my first 3 all roos. Is that coincidence or is something else going on. I do not want to think that any and all of my white chicks will be roos. I am sure it is quite evident that I am chicken genetic knowledge deficient. Detailed biology has never been a strength of mine.
One hatch is not enough to determine if your hens are predisposed to producing cockerels. Every one that hatches regularly will tell you that sometimes a hatch just turns out to be all boys, or all girls. Usually it's about a 50/50 split, give or take. An all cockerel hatch was not caused by anything you, personally, did or didn't do.
A 'split' for white, bred to a bird without the recessive gene will produce only about 25% 'split' chicks. And there is no way to tell by looking at the chicks, which are splits and which aren't carrying the gene at all, until you start hatching their eggs.So I have a chance if my black/blue roosters. If they came from a splash breeding that had recessive white gene that produced them. They could then breed with one of my splash hens and if she also has recessive white gene could produce white. Wow I confussed myself!
