We have a coop we built ourselves. It's good as far as keeping our chickens protected. We lost 3 babies in the beginning because some kind of animal pulled them through the holes in the fencing. That was an awful mess, but we fixed it. What we failed to prepare for was this past winter. We covered all but a foot or so of the door and covered up the window. Apparently, it was good enough because we didn't lose any birds. Next year I don't want to settle for "good enough". I want their building to be warm enough that even a person could hang out in there comfortably. What is the best way to heat their building. It's a small building and a space heater or kerosene heater would be way to risky in there.