Hi Jessica. I had an 8 year old Langshan rooster who had similar symptoms. He started with weakness and lying down a lot, but could walk around when he wanted to. My vet thinks he suffered an injury, possibly to his spine, and he eventually couldn't support any of his weight or stand on his own. I moved him indoors and braced him with towels to prop him up. He continued to eat, drink and poop. He would flip himself around and end up lying on his side, so I would prop him back up. We treated him with Meloxicam (an NSAID) for 2 weeks, but it didn't help him and after many tears we euthanized him.