We got him back in late winter he was able to walk, albeit somewhat unstable. He had to occassionally use his wings for balance, and we treated him for what we thought was bumble foot, but he never re-stabilized like we thought he would. It seemed like it was something more than bumble foot, but we couldn't find anything wrong other than his lack of balance. After a while, we found him one night having been beat up by one of our hens (we know it was her because she rushes out to beat him up if he's outside unsupervised), so we separated him for a while so he could heal, but now it seems like he can't walk at all. He's 1-2 years old, and we got him from someone else when he was already an adult, along with a few hens (including the one that keeps beating him up). He eats and poops just fine, and he would regularly hang out by a water trough and just drink all day back when he could walk, but he always stuck his butt out in the air while sitting or walking, making him super top-heavy. None of the other chickens have it, and I've noticed he also is missing a fair portion of the scales on his toes- as well, the balls of his feet are squished flat next to his toes, like he only walked on the front of his feet.
I've been looking into chicken wheelchairs, but I don't know the source of his problems and don't know if it'd even help. Whenever he tries to walk, he sticks his butt in the air, stumbles a bit, flaps his wings a lot, then either falls over to one side and sits there or tumbles forward and ends up just sadly rolling around. If anyone knows what's wrong with him, or if this even can be fixed, I'd love to know. He's gentle with the hens and friendly to people, so I want to keep him as long and as healthy as possible.