Hi all. I'm fairly new to chicken raising (doing so for about 2 years). Anyways, we hatched some chicks from a bator this spring and summer. A few weeks back I had a chick or 2 die suddenly, without any prior symptoms, not at the same time. I attributed it to them being young and moving them to an outside coop too soon as they were about 6 weeks old at the time and not fully feathered, and we did have some cold nights here and there (odd in the middle of summer). Also, I thought maybe over crowding. I have since thinned them out a bit and have split them up, and everyone free ranges during the day. But then, 2 weeks ago, I noticed one in the morning came out of the coop, and seemed like it couldn't keep it's head up. It did not seem painful in the neck or anything, just if you lifted it up, it would sink right back down. That was an 8 week old Buff Brahma chick, and it died later that day. It's crop was empty, but other than that, no other symptoms (didn't appear picked on, trampled etc). Now just this morning, I go out and there is another bird, a buff brahma/leghorn cockerel (10 weeks or so), doing the same thing. These birds have all been housed together. My main concern is that it could be something contagious? I don't want my older hens and rooster to catch whatever this is. Any ideas?