Heres my old coop. Only 4x6, 4 high. Had 8 to 10 birds. Roost bar was halfway up inside. Uninsulated, did not run any heat. Waterer was outside on a heated base.

Nice set up.

Got to disagree with this. Air flow-moisture is your bigger problem in the winter.
Chickens can take a lot of cold. When it gets well below zero Patrice rubs their combs with
Vasoline to help prevent frostbite. No heat in the coop here, vents on all 4 walls. Just a heated waterer, water supply in the winter is very important.
We only keep a half dozen hens or so and makes it pretty easy to care for them.

Zim

Zim, do they have access to outside all winter?

Yep, they have a 4x10 outside run with a roof on it. I plow them out all winter so they have a path to walk and range around a bit too.
They will cruise around quite a bit if the snow on the path is not over a couple inches deep.
I really think fresh air and a bit of exercise keeps them healthy as opposed to shut in.

Zim

Steve...when buying birds..buy the birds suited for your climate (hearty birds)

I have the coop windows closed for the wintah...but have the soffit vents the length of the coop ..on both sides of the roof..for good air flow up top.

No insulation...no heat

Good amount of fresh straw on the floor come wintah time is applied.

There is a hot plate ,that the waterer sits on ..which gives off some heat

And those hearty birds ,heat up the coop on their own...just by being in there.

Sometimes when's it brutal out...we will throw them some sunflower seeds soaked in bacon grease.

And other protein...to help them keep that furnace going.

I have 2 buff orpingtons, 1 old english bantam, 2 sapphire gems, 1 silver laced wyandotte, 1 colombian wyandotte and a buff orpington rooster. The rooster has pretty good sized combs, might be an issue.

Here's what a frost bit rooster looks like the morning after. The hens then pecked the the bloody feathers and he is left with a naked neck. Wasnt pretty. We culled him soon after for behavioral issues. It was the day I found him like this that I added more venting to the coop.

My chickens always had access to a small run and were free to roam when I was there to supervise.
We do get temps substantially below 0F with windchill, but they are not sustained longer than a few days generally.

Nessie's comments are in keeping with my experience (but it sounds like it gets substantially colder where you are)... I had 6 generic brown layers for 5 years. They were all quite healthy for their entire lifespans (they were given away in year 6 when our house burned and we moved to town and all died in that year).

I ran straw in the nesting boxes and pine bedding in the "common areas"

In cold months, store bought feed was provided as free choice and yogurt, scrambled eggs or bacon grease given to supplement protein.

non insulated coop, but sized for 12 chickens, roost poles off the ground and just enough for the girls to huddle together. did have heated water. They weathered the cold fine, but we rarely get to zero...

We have two coops, Both 8 x 6. Found that heated water buckets work best for us, Easy to clean in winter time. When it drops below 35, Each coop has a heat lamp. I use a string of clear led lights after the time change.

Yeah no insulation here got a 8 by 12 I justopen the door in the morning they free range close it the evening ...I recommend putting Vaseline on the comb if you feel frost bite is a issue

A heat tape placed on the bottom side of the roost pole will solve a lot of frost bite problems. Don't put the tape on top of the roost pole. If their feet are in contact with the tape it can burn them.