The past two weeks we have had excessive heat with most days being between 98-104. The vents are open on the coop. I let them free range, so they can find cool earth under the coop to burrow in and other shady areas. I also make sure they don't run out of water, although I can't always keep the water cool when I have to be at work all day. As of today we have lost 7 chickens, including my best boy, Sterling from apparent heat stroke. However, it has only been my adult chickens (all around 14-16 months old) who are being affected. We are finding them in the coop, usually the floor, but two were dog piled in one nest box. This coop is no worse than the others and better than some as far as ventilation. Could their be other health problems at play? What's the best way to keep this from happening again.