When i went out this morning to let the chickens out i found one of my hens on the low roosts with both her wings spread out and her head falling off the roost! She has ( what looks like) egg white and yoke dripping from her vent and it seems like she is trying to pass a egg. I had three of my other hens doing the same thing last week but none of them where like this! I'm really worried because she can't stand ( she has no balance) and she wont eat or drink. Dose anyone have any idea what could be wrong? And what i can do? Please help me!! I'm still new to keeping chickens and i hate to see her like this! can any one help?