Hi There!!! I have a 6'x7' coop that I built. We have 6 young Chickens and it's starting to get cold here in upstate NY. Right under 3 sides of the roof is a half inch vent that goes for 6 feet. Would that be enough? And should the vents be under the roof line but above the roosting bars? I was worried that all of the heat that they generate will go right out the tallest part of the coop. How do they keep heat in the coop in the winter if the vents are at the highest part of the wall under the roof? Thanks for any advice!