It would be better to have one end that is cooler so that they have a way to get away from the heat if they need to. They are stronger than we think. I have a hen that hatched 3 chicks and had them out in the pasture, on a cool and blustery day, when they were a week old!!! She didn't seem to be at all worried that all of the books say that they have to be kept warm at all times....