Welcome to BYC.
You've gotten good advice so far from people better suited to give it than this hot-climate person.
But I thought I'd clarify a couple points already made.
First, this is my article on coop ventilation:
https://www.backyardchickens.com/articles/repecka-illustrates-coop-ventilation.77659/ It will show you how to achieve excellent airflow without any drafts blowing on the birds. The goal is to have the temperature and humidity the same inside as outside but to protect the birds from any breeze strong enough to ruffle their feathers.
Second, one of the major downsides of insulation in a chicken coop is that it provides a grade A, cozy, secure home for rodent pests.
Third, being in a location that's prone to weather that's both wet and cold, if you use metal roofing -- which has many advantages including durability and ease of installation -- you could have a condensation problem.
While providing a good flow of air under the roof is always good and is adequate to prevent condensation on metal in a mild climate, if you choose metal roofing you will want to create a thermal break either by installing it over plywood instead of on purlins or using some kind of insulation under the roof -- rigid foam board being popular for such applications.
Just beware of putting any kind of foam anywhere chickens can reach it. For some reason known only to the chickens themselves, they LOVE to eat styrofoam.
