So these guys fly, so that is clue one that they aren't really Silkies. Their wing feathers were completely developed when they were 3 days old and they were fluttering to the top of their brooding box, while the RRs and Ancona of the same age just had fluffy stump wings. They're only a couple months old and they began crowing already! We adopted them from a flock that had a black Silkie rooster, so that part makes sense. Other birds in the flock included Turkens, Cochens, a Pea Hen and maybe a BR, also a white Silkie female. There may have been other breeds in there, but the flock was somewhat small. Anyway, what do you think they could be in addition to Silkie?