I've spent the last couple of days treating my chick who stopped walking for a vitamin deficiency. Talked to a chicken doctor who thought most likely it's Mareks. Read up on the disease and symptoms do seem to match, as the chick does seem to have paralysis in the legs. She was supposedly vaccinated, so how did she get this? Will the other three chicks also come down with it, since she has been with the others while sick. From what I can gather this disease is spread through the dust on the wings getting in the air, so no keeping exposure to others away anyhow. What do I do now? Do I have to put her down? What does that mean? Can I protect the other chicks or just hope that their vaccine works? What do I need to be concerned about for any future chicks? I feel like I'm going through chick raising boot camp right now.