For a few days we noticed one of our roosters seemed to be tripping a lot. We checked him for bumble foot, turning him on his back to do so. No bumble foot but when we sat him down he fell over, acting like he was "drunk". We sat him on his feet and held him up. After a few seconds he seemed to regain his footing and though a little wobbly he was able to stand and walk. He was put into a separate coop for the night. The next morning he was laying on his back with his feet in the air, unable to get up. We brought him inside and checked him over. His weight was good and other than moulting and new feather growth, seems physically fine. He's eating and drinking, I've added poultry booster to his water but he can not stand on his own. His legs are not paralyzed. He can use them and when in the harness we rigged for him he can stand and push but he can't walk or stand without the harness or propping. I've researched every thing I can and nothing seems to fit exactly. Any help would be greatly appreciated.