I live in MN and it is COLD already, but my 4 hens are doing great in the Eglu. I have the winter jacket around the coop and the weather protecting cover for the run, with deep litter that I turn (dried leaves and shavings). The Eglu has kept them nice and warm, and they seem quite content - you can feel a poof of warm air when you open up the Eglu. That said, I know this is the land of extremes so I bought extras. My husband teases me about $100 per egg costs, but my girls are happy, warm and dry without a heater.