Amprolium medicated chick starter isn't a problem! Hope your chick responds.
Several years ago I had one chick (out of fifty!) who had this problem, and as she got worse and worse, I euthanatized her and had her necropsied, because I was worried about possible Marek's disease. She had severe brain lesions from vit. E deficiency and wasn't going to recover. The feeling was that this one chick had a higher than normal need for vit. E, a genetic issue for her. That's why I mentioned not having your sick baby in your breeding group later. Your other chicks are doing well, it's just this one. So sorry! Mary