I've thought of the heat outside and will put a sun roof or awning over the nest box egg tray. I use large hoop coops and leave a lot of end space open for ventilation but then blowing rains wet the ground inside the coop making walking in them a hazard. l thought about paving a walkway with drive way gravel but don't like it.That is a good and maybe a little bad thing. I know you probably already do this but if you go in (unless it is one of those tiny coops) due to having them roll inside, it gives you the opportunity to check and maybe clean the nest boxes. Also it will keep the eggs cooler. If the collection point is outside in the sun that may not be a good thing.