Hi. I'm new to owning chickens and so far I love them. However, one of mine recently started having problems walking. She eats fine and drinks plenty but she can't stand up properly. She seems to have something really heavy pulling her chest down. I have researched some stuff and I can't find anything like this. She seems happy enough. There is no problem with her legs. She tries to stand and can get her back side up but has to balance herself on her beak to stay up. She's my favorite and I really want her to get better. Please help!!