As everyone has been saying, insulation will do nothing in a properly ventilated space.
Feathers are very warm. Chickens don't need help staying warm.
They just need the breeze and strong drafts kept off of them so they can keep their feathers poofed.
They need dryer, fresh air to keep their combs from frostbite and their sensitive respiratory systems clean of harmful gases like ammonia.
Too many people build their chicken housing with a focus first on what humans want to look at (and then post their designs all over the internet), rather than what works best for the birds.
Once you build it, changes can be very difficult. And bigger is always better. Especially in the run where they spend most of their active hours.
If I lived up north, I would absolutely pick a Woods coop like
@3KillerBs posted. It's time tested.
Probably all of us ladies on here have had dudes "build us something" and wound up with a result that didn't meet all of the needs.
Anecdotally: My father was a builder who fancied himself an architect, and the way he could mess up a kitchen... I can't even describe. Yes, they all had a sink and stove, counter and oven and fridge. But because he didn't cook, he didn't understand work flow for that task.
It's the same with poultry keeping, you have to think about what it's going to be like harvesting eggs, cleaning, feeding and watering, raising chicks, all in that space. (storage is something I sorely wish for)
And the same from the perspective of the birds.
Do they have room to stretch their wings to fly up and down from the roost, with other birds doing the same thing at the same time?
Do they have enough distance between the roosts to avoid pooping on each other, or all over the wall? Are the roosts high enough they feel safe? Are the nest boxes low enough they choose the roosts for sleeping? Is the air clean and free of excess humidity? And so on...
