From what I’ve read 1sq ft per hen. If I where building one from scratch, I would have the whole South facing side open! This would be into a covered run area to keep the inside dry. On those windy days last winter we had snow blowing in if we had the windows open. My repairs this summer took that into mind. We get “nor-easters” with strong winds from the north and east. Our run is to the north. I built a whole new run and mocked down half of the south wall. In the picture above the Camra is pointing West. That upper area that’s covering the new opening has the east face.
With a new coop I would also include fixed roost poles above poop trays. Power to keep the water warm in winter along with lights so I can see the birds at night. Plenty of nest boxes too! Food and water is moving out to the covered run for us. It should help keep everyone happy by having multiple feed/water stations. Also we have a small tractor/loader we use in the garden, we load weeds and dump them to the grils to compost. Having a gate big enough is important to us!
The south side on this coop would actually be where the door is going to be. East will the door for the chickens to go into the run. The north side of coop will be facing a bunch of trees. The good thing here is that it's not a wide open area like in the country, so done if the coverage like trees and the fence to the yard is going to stop quite a bit of the wind. I don't want to put the door on the side because it won't be in my line of vision, but on the other hand if I do that then the open ventilation area will be in my line of vision and less accessible for predators. Not a bad idea.