How do you know if how much ventilation you need? I have 5 chickens that roost in a roughly 3' x 5' coop. I haven't been shutting their little entrance door so air can enter there. I am considering caulking the corners, but am still confused, drafts vs. ventilation? I am considering making an insulating "blanket" to put over the entire coop at night. but not sure. after reading other threads have decided not to heat. Still trying to figure all this out! In the warm weather the coop has a 12" x12" window I leave open. but I have closed it now to help hold in the heat. Any comments or advice appreciated! In Maryland!