It's a 4x8 coop. I plan to add a total of 10 vents, can add more if needed, there is plenty of room and vents. They are placed at the very top, so they aren't near the roosts. Winters aren't too cold here in southeast texas like 40's, maybe 30's if its a really cold winter. The vents measure 4 by 16 inches. Things didn't go exactly as planned. The wood didn't get cut out before putting up the wall, he forgot. So s hole saw was used to make holes. Which i think might noticeably lower the ventilation. I can get a bigger hole saw and have him make bigger holes if needed. Going to have 6 or 8 large chickens in there if that's needed info.