I bought 6 chicks and they're about 12 weeks old. One (silver laced Wyandotte) was not vaccinated against Marek's (I just found out), and she got it and died (had a necropsy done). Now another chick (Ameraucana) is showing the same symptoms: not able to pick up her head, won't/can't eat or drink, just lies there! Poop is a little runny, but not bad. They eat Purina start & grow, I feed them some yogurt about every other day, and lettuce/greens each evening. I give fresh water every day, and clean/clorox the waterer every few days. They are in a Catawba Coop in a natural area with a thick groundcover of leaves (I rake out one end so they can get to the dirt for their bath). I move it once a week, and clean out the pine shavings from the roost once a week. If she was vaccinated, then it can't be Marek's, right?? Any ideas??