I am a new chicken owner as of July. I live in west-central Minnesota.
It is colder here in certain snaps than ANYwhere else in the lower 48, I tell you.
There is an exchange student here from Norway, who lives in the COLDest part - Artic circle material - who is so very sad and disappointed that here, in MN, it is COLDER than where she is from.
We live in a very special cold and windchill blessed area of the country, I tell you. Again.
I hate being cold. With every fiber of my 41 year old, nerve damaged, arthritic piano playing hands/fiber of my being.....I long for warm Colorado sunny winters. Although I grew up in MN, I miss you, CO!!! I'm coming back!!
My chickens are in a backyard coop in town. A Rhode Island, an Australorp, and 2 Silver laced Wyandottes. The coop is not insulated. 4x5 run underneath coop and south facing 'chicken porch'. It's been -20 or more for a week.
I am a softie because I don't like cold. But I know the chickens can handle more than I can. I have compromised and purchased a ceramic flat panel heater. Plugged in to a regulated thermostat, it goes on when outdoor temps reach 0, and off soon after. The chickens go into the run voluntarily all day when it's been -10 to -20....as long as they are out of the wind they seem to be fine. Cranky and bored at times, but JUST fine. ALL day. At -10 to -20.....out of the wind.
So the ceramic heater is just a stress reliever. I have less stress worrying about 1) cold chickens and 2) my first egg yet to be seen!
Also, no concerns about fire at ALL. Have vents and windows open to keep temps hovering around 0 degrees in the coop.
Many weeks ago my oldest hen (RIR) started 'chatting/squaking' at and with me. Non stop. Like my teenage twin daughters.

Then, the Australorp started caaaaawwwawaww -ing at me.
THEN, yesterday, I got the submissive squat. From Kevin the Australorp. THEN....I got the squat from the RIR. SOOOO exciting! First eggs coming right up, first eggs EVER!!! Wheee!
Hooray for the flat panel heater to reduce stress!
peace and blessings to you and your chickens.....