I have seven chickens between 4 and 6 weeks old currently. My coop (formerly used for chickens by the previous owners of the property...I think they had a lot more chickens) is 8X12 and 10' high. I took out the wood floor and having a concrete floor poured this week. I was wondering if I should put some plywood up to create a ceiling to keep the heat down closer to the birds. Also, I saw on the coop page that all of the coops have ventilation systems as well as windows. If I put a grate vent at the top of the wall, won't it create a draft in winter? Thanks!!