Chickens really do well in the cold , their fluffed feathers are like wearing down parkas. My first winter 2020 as a newbie my hubby and I were so fearful of the cold, (that was that terrible polar storm that went clear to Texas)! But unless it's blowing and/or wet they hang outside.
One BYC member here brought up a good point, that if you heat coop they don't grow as "tough" and if you lose power they aren't as capable in cold as those that have been raised with no heat. My first year I kept on a light bulb to keep warm but I didn't last year after seeing them choose to be outside no matter what. Just a FYI.
Now conversely they HATE hot and that's were the work at keeping them cool comes in, which is exactly

opposite of what I thought as a newbie.
I did add a heated waterer which keeps water warmish and helps keep them warm in winter though.