Some Sunbeam heating pads have had that problem, I've heard. But the model we are using has had no issues. A few pages back in this thread someone posted a link to a heating pad and the reviews were bad. But others did some research on that link and found it that the reviews were actually for a different pad an posted under the wrong model. http://www.amazon.com/Sunbeam-2013-...kmr1&keywords=Sunbeam+x-tra+large+heating+pad The smaller version of this heating pad was on continuously for several weeks for Scout both when he was in the house and when he moved outside, even in temperatures of 6 below zero and lower. No issues at all. Then I had the larger one (the one in this link) on for a couple of months with no problems whatsoever. That one ran in temps that varied from a balmy 50 degrees down into the teens. I will say this, though. If you have any doubts whatsoever, don't use MHP. I'd like everyone who expresses an interest to give it a try, but if it's not for you - if you don't feel safe - then don't worry about it! None of us want you to try anything that makes you so nervous. The ultimate end result is healthy strong chicks, and no matter what you end up doing, if you have that you have it made!