One of my hens has been laying around on the ground and when one of the other chickens come near her she moves around a little. When she tries to move around she looks as if she is crawling, kinda almost dragging her tail end, with her tail all tucked down. The others have gone to roost, she went in the nesting box for the night. I do not know what might be wrong with her, anyone have any ideas??? The only thing I could think was maybe she was egg bound? Thanks for any and all suggestions/help.