I had something similar with my flock. Chicks that started out with red down feathered in as black. I can't find a genetic reason for this but I think it was some type of melanizer a breeder was using to decrease leakage in her black birds. It was hard to get rid of.
Not all white hens give sex linked chicks with a red rooster. It depends on the genetic make-up. White Leghorns practically never do. White Rock sometimes do. There are two ways to genetically make a solid white chicken, Dominant White paired with Black and Recessive White with anything as...