Also remember that rumplessness can happen just by accident. That means he won't be passing his rumplessness on to any chicks if his rumplessness was just something that happened as he formed in the egg instead of being controlled by his genes. I have a rumpless silkie that I'm pretty sure is an accidental rumpless. His breeder said that's the first time she's ever had a silkie hatch out without a tail and she's been breeding for about five years. The kids fell in love with him and we took him home since he was otherwise a healthy little chick. He was four weeks old when we got him because most of her customers are looking for chicks with SQ potential. We were looking for pets. But if we bred him, we'd probably never get a rumpless unless another accident happened with tail formation again. That's highly unlikely.