Yes, i plan to make it for full walk in (same as our current one). I currently have a ridge vent, though mice have made a nice home there (and a mess), so i will do gable end vents next. I usually use Zip tape around windows and penetrations to help cut down on wind. Havent noticed a problem...
I like in Upstate NY and I am working on a new design for my coop. My current coop is about 5 years old and I built it quick and on a budget. I used TPO roofing for the floor and it has mostly been great to clean up after, though now I am wondering if I need it. I am in a fairly sandy area...