Hi there, my female is expecting a small litter (3-4 pups) in two weeks. I've been looking into different heating pads that would be safe to leave in the whelping box for added warmth, but can't seem to choose one. I saw that the Lectro-Kennel had some very bad reviews on Amazon, and in one instance caused burns..so now I suppose I'm paranoid. Any good tried and true brands that any of you have used? Thank you!