I had a hen paralyzed for about 3 months and lived. I kept her in the house. I gave her a vitamin b complex pill everyday, poultry cell in eggs and selenium with vitamin e. I would also massage her legs a few times everyday and stretch them out. I also made her a sling with a storage bin so she could stand. She is back out with the flock. I dont think it would be a vitamin deficiency after that long but mareks. They normally die within a week of showing signs. Don't give up on her it takes time and patience but she can survive. If you don't mind me asking was there any signs before she couldn't walk?