I have a female Pekin approximately 7 months old. She has been healthy with no mobility issues until tonight when we found that she hadn't cooped with the rest of the birds. Both of her legs are splayed out straight behind her. When you pick her up and invert her, she will draw her legs in and spread her tail feathers, but as soon as you put her down her legs go straight out. She has no evidence of injury. Any ideas on what's causing this and how to fix it would be appreciated.