It sounds like you are going to have a lot of chickens in there, in which case, 1'x2' is not even *close* to enough.
Surely you're not going to have wall cages on all 4 walls, thus you could have at least one of them consist largely of openings (with flaps or whatever to close them down when needed). Also you can put vents up at the eaves or atop the walls, protected by the roof overhang; even if you have to shut some down in the coldest windiest weather if there's a cage hanging right below them, or something like that, you will get good benefit from them most of the time.
Seriously, if you do not put a LOT more ventilation in there you will be looking at significant problems with stink and air-quality and (in cold weather) frostbite and (in summer) overheating.
Good luck, have fun,
Pat