I have a 2 month old baby barnevelder that was stumbling the other day. When I picked her up, she had a bubble on her shoulder. As I lightly pressed on it, it went back into her body and expanded her crop a bit. She eats, but, 4 days later, she is slower than the rest of the barnies and she stumbles, almost convulses, if she attempts to run. If she's getting better, it's going slowly. Has anyone ever had this happen to one of their chickens. Did a big hen step on her and push her crop out her back?