In a nutshell, I got 6 chicks that were approximately 1-2 weeks old. One started to look sick about a week after I got her and she still isn't great, but she's not my immediate concern. (just an FYI - when she started to seem sick, I treated the flock with corid for 7 days as I was worried they might have cocci even though I saw no bloody poops). The one that always seemed the healthiest was my EE, last Saturday she seemed less active, but it wasn't alarming, by morning, she wouldn't walk. Once I noticed, she went downhill fast. We moved her by herself and about 15 minutes later, I watched her die. It was heartbreaking. She was so healthy. She has no symptoms other than the night before, she was easier to pick up and didn't seem as active. Two days ago, (so they're right about 7 weeks) I noticed my second healthiest seemed less active, though she has always been calm. She was still eating and drinking but it had me concerned so I got some nutri drench and some meal worms in hopes that it would give her some energy. This afternoon, she was laying there and wouldn't get up, finally she got some water but she's in a dire situation now. She won't open her eyes, won't stand. She looks just like my EE did before she died. I do not understand. I've read so much and nothing seems to fit. A respiratory infection seems unlikely as they've never coughed or sneezed and have no drainage... they seemed so healthy. In case anyone is wondering, they are eating purina start and grow medicated. They have only been inside... they've already had a corid treatment and they are on medicated feed. I just recently moved them to the garage, I turn the red lamp off unless the temp dips below 60 which has only happened a few nights. I think the temp is fine and they're mostly feathered. I did see lice on all of them two weeks ago but I dusted them and haven't seen anymore, I was going to dust again tonight to make sure anything newly hatched would also die. Mareks.... are they too young for this? Could this be it? I've read through posts, I'm just at a loss and I'm wondering if I should give up on raising chickens before I kill more.