3 hens in a pre fab in southern WI here. It’s been -20 to 8 degrees for almost 2 weeks. They are doing okay - no frostbite yet! Here is a pic of the coop. No heat. Just a couple tarps to keep wind out. They don’t want to come out into their ‘free-range’ space right now, so I take the tarp down when it’s sunny so they can get some rays. Coop is behind garage and along the fence - this also blocks the wind. Lots of protein snacks, extra straw and pine shavings, heated water dish, and love!
I would say no need to bring them in just to return them to the cold. Just take care of any drafts and wind, but keep some areas open for ventilation. Good luck!
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