I have been feeding and trying to tame a semi-feral cat on my property for about 6 months. The outdoor temperature is dipping down to near zero tonight. The cat sleeps in my outdoor shed. Even though I provided straw for the cat, I know cats can develop hypothermia easily. I used an outdoor extension cord to run electricity from my garage to the shed, and plugged in a drug-store type heating pad (set on low), and placed it in a cat bed with towells over it. Is this safe? How long can I leave the heating pad turned on? I'm worried about the safety issue, but more worried that the cat I've worked so hard to try to tame will freeze to death.