Hi. I noticed one of my hens was unstable on her feet this morning. When she ate she had her tail pointing down, and had a hunched over back while pecking. Her chest bone (breast bone?) seems more defined than normal and seems to be protruding. Shes acting sort of slow, and was laying down earlier. She is alert, eats and drinks. I'm not really sure what is wrong, but does any one have an idea? Thanks.