We have 4 little chicks about 5 days old. One of our Buff Orpington's tailbone is exposed. At first I thought her vent was just plugged, but she is definitely missing feathers, and the exposure looks and feels like bone. I haven't noticed her or the other chicks pecking at her behind, so I'm wondering if it could be disease. It also looks as though the bone may be turned downward abnormally. She doesn't seem to be phased by the lack of feathers, still hops around happily. Should I be alarmed? Should I just watch to see if she makes it?