My coop was built to be what I thought we needed in the beginning. It is insulated, has Marvin Windows and rectangular vents on each gable end, which are North and South. It is very nicely built because my husband is a trim carpenter and had the idea we might sometime in the future have no chickens but grandchildren. So far we have chickens. The Vent area was left open, but I went in one day and there was such fierce ventilation that the upper area was a wind tunnel. We had been unable to find the proper size pre made slanted slatted vent insert. I bought 4 cheap plastic vent covers, and that cut the gale force wind down to a pleasant freshening air exchange. I still want to have the proper wooden vents custom made, but as many details of our house also need completion, I am biding my time.