I have 12 (well now 11) hens in a large coop filled with straw, sprinkled with DE. They have a very large run made with electric poultry netting which I move regularly so that they can free range. I have a variety of chickens. Today i found one of my white Jersey Giants dead. No sign of injury or illness. Just laying on her side dead in the coop. Cold and stiff, it may have happened yesterday. She was about 1 1/2 yrs old. A large, gentle chicken. I live in Martinsburg, WV. It was very hot here this weekend but they have plenty of water. Any ideas before I lose more??