We live in North Texas with two Red Sex Links about 2 years old. Their egg production had started to taper off, with one egg, sometimes two, a day. Yesterday they were out free and acting normally until around 1pm, when we had to leave the house for the day. We put them with food and water into their coop when we left. This morning, hubby took out fresh food and water, but the girls were not active. That should have been our clue. This afternoon I checked on them and they were dead in their nest boxes. No signs of predator, no signs of trauma, they looked like they'd been sleeping and simply died. Their food from this morning was untouched, so we think they died during the night. Last night we had some rain, and it was warm. The coop has an attached covered run. The door to the run is left open in the summer, there is heavy-duty screen (hardware cloth) under the eaves of their coop, and there is a window about 8" by 10" in the door of their coop. Do you think it's possible that heat killed them or should we look for some other reason? Thanks so much for any help you can provide.