OH DEAR, I've had chickens for 30 plus years here and never had a case of well ... anything! I've looked it up, and it sure sounds like MD. Except none of them have any eye involvement, at least at this point. I'm going to call around tomorrow and find out if I can have a necropsy done, and in the mean time, I'm going to hope it is B-12 deficiency and I'm going to get a group that appears unaffected at this point, on vitamins.
These are my only young birds, thankfully.
I've never opted to have hatchery chicks vaccinated. And unless it is the right 'strain' of a vaccine for a virus, I don't think you get much protection. Like vaccinating for a cold...
Thank you all for such quick responses. I will update.
I vaccinate, and give my breeders a booster every year, ever since I started that I have not seen it in 5 years.