So, I live in north alabama, where we get one day of snow a year (read no snow load), and only maybe a week of freezing temperatures on a normal year (this past year has not been normal!). I keep mine confined 24/7 due to predators in a covered run entirely covered with 1/2" hardware cloth and with a 3 ft apron around each coop. I don't have a traditional coop. I put perches in their run, and I'll put up plastic outside the coop and pieces of plywood up for wind blocks in the winter time as needed. It gets so hot here in the summer, we need as much ventilation as possible - both ends of my hoop coops are full mesh. My best coops are a hoop coop and a green house frame hoop coop, with a tarp over the top of both.
I found that if I give my chickens less than 15 ft of space per bird, I get awful problems with feather picking in the winter time, and bullying year round, and overmating when roosters are involved. Need a cluttered run, things to do, and stuff to hide under and run around to block line of sight. My chickens have access to that 15 ft of space per chicken 24/7, and that helps to have a calmer flock and less drama/fighting/bullying. I've tried to do 10 sq feet or 12 sq feet per chicken, and it didn't go well. My flocks are mixes of ISA brown, golden comet, orpington, prairie bluebell, starlight greeen egger, etc.