This morning I went out to my coop at 7:30 ands all the birds seemed fine. I went out again at 10:30 and found one of my buffs dead next to the nesting boxes. No signs of any injuries, no blood, feet cold and comb blue. She was still molting and a bit thin. Any idea what might have happened? My best guess is heart attack or embolism. Is this common? She was only 15 months old.