I haven't had mine too long. I hatched chicks and they have started laying and I've started hatching those chicks. I found one breeders website where they mentioned they get around 30% of chicks that are entirely black (no pink toes...). Granted I haven't had time to really cull chicks and selectively breed for all black but I'm getting no where near 30% that are all black. If I hatch 10 eggs then I might get 1 that is all black.
Those of you more familiar with the fibromelanosis gene, is it worth trying to heavily cull chicks with any pink and only raise those that are all black or is it that no matter what I do, the gene has such a variable expression, that no matter how much I cull I will still get a significant portion of chicks with some pink toes?