I've never had a problem with dex overheating in a hammock, but if its hot up there he will find a cooler place to go. You can look at his ears too since chins let out heat through their ears (if he's starting to overheat his ears will become red and veiny). Dex loves his hammock and lays in it all the time to watch tv and like I said no problem, but I always keep my thermometer at the same level. Hope that helps:)