She was fine yesterday, I sat with them for awhile and everyone looked normal. I checked her over and can't find any marks, blood, broken bones, etc. her eyes were closed. I checked for discharge in all of the normal places. Everyone else seems fine. She was 8 months old and a nice heavy bird, a silver Wyandotte. I'm very sad, she was a pet and named after my mother. My fear is that others will die too with no signs of trouble. Can anyone give me some ideas of what could've happened? Btw, our weather is mild, in the 70s, no rain and she was in a very well ventilated coop.