My coop is 4' x 8' and has 2 -6" x 24" vents at the top of each side of the slanted roof(4-total). How close is to close for the chickens to roost to the vents? Should I put a piece of plywood on the inside to act a a damper so they wont get a draft? I was thinking of plywood on the 2x4s on the inside so it would still draw air in and out. With the 3-1/2 space for air to still vent but couldn't blow on them. Will that be enough air movement in the coop? Too Much? Any Ideas?? Right now the are roosting about 6" lower than the vents but with winter coming and our changing wind direction ,I worry about how much air they will be getting on them.