I've had a few chicks hatch out perfectly. No problems at all, every thin including their feet look fine. Then around 7 to 10 days later I notice their toes starting to curl. By two weeks they look like a fist. It's not from one breed or one breeder. I get one from almost every hatch and every breed. Why????? what am I screwing up now???? I'm feeding chick starter with an occasional meal worm treat.