I had a partially sighted pullet, about whom I wrote an article. I've had a couple of roos that needed special care after fox attacks, one of whom I wrote a thread about.
I'm currently dealing with the ex-dominant roo, who I think caught avian encephalomyelitis, or something that has very similar symptoms, and who is making a gradual recovery. At his worst he could only lift his head, he couldn't even sit up, though his legs retained all their strength and flexibility. The first photo was taken at the start of that phase, when I had found him on the floor of the coop and brought him in, having no idea what was going on. I had popped him in a washing up bowl but he kicked and tried to stand, only to fall out and over.
I should add that I had never handled him before this time; he was used to ranging free since he hatched.
He endured about a week lying on his side - only the right side; if I tried to turn him over to avoid pressure sores, he'd go into a frenzy to get back onto the right; he never lost his strength or use of his legs and wings; he just couldn't control them. He was not capable of standing, sitting or pecking, but his comb and wattles stayed red and his eyes bright. His whole body had tremors, intermittently. If it was AE, I think the tremors were caused by inflammation on the brain. The nadir was 5 days later. He needed intensive care, getting water by syringe to the side of his beak and live mealworms, tinned sardines, wet dogfood, milk-soaked bread, banana and suchlike to the beak to eat, little and often, when he was not in tremor and receptive to it. If the senior hen came in to visit him, he chatted enthusiastically to her.
By the end of the first week he'd turned the corner and after 8 days inside he was trying to right himself. We found he could sort of prop himself up in the bowl against the units.
The weakness was in the right side only. After another week he could sit. And he resumed crowing. He tried to stand to eat but fell heels over head for the next couple of days. His balance is still not right, and he still cannot scratch, but he just resumed preening this morning - another milestone on his road to recovery. When a hen or two comes to visit (some of them have been in to see him [or rather his food bowl

] almost every day, and he likes to pretend he found those goodies

) he stands up straight, flaps his wings, even tries to do a dropped wing shuffle, and it's the best physiotherapy session imaginable.
He came inside on 22 June and is still a work in progress. This was taken at the start of this month, when he got first dibs gleaning the mealworm drawer; he jumped out of it afterwards.
If we did not have 3 other roos he would have been back outside last month. But they won't tolerate him like this, and I am still working on a long term solution.
This was him before he fell ill, and how I hope he will be again one day.