I'm new to having chickens in Fairbanks, AK and am looking for some advice on whether to heat the coop, what temperatures to heat it at, and what heat source to use. I had chickens in Minnesota and they did quite well with no external heat source, but it's not unusual for us to get weeks of -40F here. I have six Rhode Island Reds born this spring in a very well insulated (with vents) coop that is 8x8x8. Do I need to have a heat source? What temperature should it kick on and off at? I found a plug that will do on at 0 and off at 10, that's the lowest temps I could find. What's the best and safest to use? Do I continue to give them the option to go outside through the small door all winter, thus leaving the coop open to colder coming in through it? I want the ladies to be as prepared as possible for cold weather and possible power outages, while also making sure they are comfortable. They will have a normal light on in the coop during the day, but it doesn't produce heat. Also, anything special they should get in their diet to help?