I have a new batch of chicks and a few of them have pasty butt. I've been watching them closely, trying to make sure I can get them as clean as possible without hurting them, but two of them have gone almost completely bald on their butts! They're barely 10 days old so I'm a little worried. Any ideas if this is normal? I've never noticed this in other batches of chicks I've had in the past. One is a Barred Rock and the other is a Delaware.