This is something I never thought about till I got my laser thermometer(I have been checking temps of everything since I got it today, dogs nose, tv screen ect..) Well I feed my snakes frozen thawed and have never really had a problem with them takeing it at room temp, sometimes I put it under the lamp but dont always have to. That being said, if I really wanted to be precise what is the average temp of a live rat and should I heat the rat to that temp for a quick feed?