One of my hens has been sitting in the nesting box all day. She's not acting quite right. She did come out once at my urging to drink and eat a bit, but she was walking slowly. She also did a big poop when she got up, very big and watery, but no blood or mucous. When I pet her, she usually plumps herself up and spreads her wings, but today she just sits there making little clucking noises. What can I do? She's my sweetest hen, I don't want to loose her!