Sorry I don't have any experience with pig blankets, etc.

But I wanted to ask you: what are your plans in case of power failure?

I live in Missouri, and while it is a little warmer here than in Denver, temps can drop to well below freezing (and sometimes below zero F), and we have power failures. I keep my russian torts indoors during the winter and let them hibernate in a cool spot in the basement. A power failure would not result in a catastrophic drop in temperatures in the basement.

Best of luck with your plans!