Was around the farm all day, chickens all acting fine. Had water and feed. I had given them some partially ripe tomatoes for a treat. Left home about 3pm. The birds in this coop were all in the enclosed, roofed run. It has 1x2 welded wire fencing. Went to visit step-mother who just got out of hospital, then wife and I had dinner. Got home 4 hours later. One golden Comet dead on floor of run. She was 24 weeks old. Had been laying about 4 weeks. No sign of egg bound or crop problem or bleeding or injury or pecking. It was not hot out. They had food and water. I never understand this. I know it occasionally happens, but is not ever good.