BCR, the side with the hides is the side that sits on the heat tape so that's the hot side. My rack is enclosed and its always dark in the shelves. I have a very picky eater who has yet to eat for me ( I've had her three weeks today). Her tub has a hide, I may take it out and then try to feed her on Thursday, as that's feeding day. The other three are excellent eaters and have not missed a meal since I've got them (unless they are in shed). I may just take out all their hides and see how they do. Thanks for all the advice.