This will be interesting to follow, sorry for your loss. Last summer I lost 2 hens in a few hours. I found them in the coop, one in a nest box and one in the middle of the floor. I was guessing they died of the severe heat and humidity we had that week. fine one minute gone the next. They were a couple years old as well, not sure on exact age as I got them from my neighbor who is getting to old to care for them. Coco was a beautiful bird, again sorry for your loss.