I have an almost 7 month old Columbian Wyandotte rooster who seems to have fallen to a sudden illness. To start, he had a difficult hatching, needing assistance. He hatched with a twisted toe, but seemed to do alright with it. When introducing him with his brother and sister to the other hens, he was attacked and pinned against the backside of the brooder on day 3. Since then I have been rehabilitating him. 1.5 months ago we bought a new coop for he and his sister so he could gain strength. He was having difficulty walking and using his wing. He would stumbled and fall when trying to walk. About 3 weeks into being in his new coop, he had gained a great deal of strength. He was walking normally and using both wings. He looked like a regular rooster and when free ranging with the other hens, he was quickly gaining dominance. 2 days ago he seems to have had a sudden illness. He cannot stand well, often falling over. He does not use his right wing. It just hangs. His tail feathers hang. His feet do not walk well together, one lagging behind the other. It seems as though his right side has suffered paralysis. I am not sure why the sudden and severe development. I have been giving him nutrients in his water and getting him out more often to free range and get more exercise, but I am not sure what could have happened and how to best help him beyond exercise and nutrient increase. Does anyone have any thoughts? I know it sounds like Mareks, but all the other 13 hens are healthy and well. Could he have suffered a stroke? His wing doesn't feel dislocated. It seems the same as the other. Any sugguestions are appreciated. Thank you.