I had two chicks, ages 11 weeks. One was a Serama, the other is a huge mixed breed. I noticed Saturday that they weren't as hyper as they normally are. I held them Monday and they were thin and listless with fluffed feathers. I found the Serama dead an hour ago, with the mixed breed chick still trying to snuggle it. I got some new chickens Thursday. They were accidentally exposed to the two chicks in question. Is it possible for the new ones not to show any symptoms? What can I look for in the remaining chick? I have the poor little Serama (one of my favorites) in the fridge. Do I need to do a necropsy? They lived on pine shavings. They ate medicated chick starter for the most part, although they have eaten layer feed for the past 5 days,because we were out. If it is Mareks, how can I contain it? These two have had possible exposure to other chickens. We have a flock of about 100. No symptoms elsewhere yet. HELP!!!!