I will preface this by saying that the chicken is now dead and has been for about three hours. Anyway, she was a Dark Cornish SQ and had just finished feathering out~ hadn't quite got her adult voice figured out yet. She was a bit skinny when I got her, but didn't think much of it, because growing Cornishes need a lot of food! About three weeks ago she started holding her wing funny (loose, like she was hot, but only one wing) , but I couldn't find anything wrong with it. Figured it'd probably just go away. Then a week ago, when this really hot (for Oregon, nineties) weather started, I found her laying upside-down with her legs in the air and her head sprawled out at a weird angle-- eyes closed, everything. I really thought she was dead until I picked her up and she started kicking. She had very little to no control over her head and neck; her mouth hung open and her head just hung loose, unless it was prodded back into place, she could hold it there. She was really hot & skinny, so I assumed she was dehydrated/malnourished and so gave her 20cc's water and 10cc's milk. She did fine with that, opened her eyes, started perking up a bit. I placed her in a cage with layena, water, milk, and used an envirocoolant thingy on top of the crate to keep her cool. For the next couple days she seemed to improve a lot, drank all her milk every day, started trying to walk again, etc. Two days ago I realized that she hadn't been moving as much, and while her poo was healthy, she was sitting in it all day. Flies had been laying eggs on her feathers, so I cut off all the feathers affected before she could be flystricken. Yesterday she didn't drink her milk, just dumped it all over herself. Today she was alive at three, dead at six. SO long story short, how much should I be freaking out? She and her boy (who is fine, btw. Big and strapping and healthy.) were separated from my other birds as new arrivals, but I'm watching everyone extra close. Is this something that happens to Cornishes regularly? She had great bone structure,nice thick legs, so maybe her muscle just couldn't catch up? They had free choice Layena pellets plus a ten by fifteen run full of grass and bugs and stuff. And, ya know, water. No oyster shell unfortunately.