She was inexperienced as a mother and it was her baby, so she was probably just under alot of stress. But, I'm not sure if they'll grow back. I was told they would by an animal biologist but that was a week ago. All of his other feathers are coming in besides the ones on the back of his head. It worries me. I really do hope they come in so he doesn't have a cold head for the rest of his life.