My husband and I have 17 chicks on order; 16 hens and 1 rooster. My husband is in the process of building the coop now. We are building a 4x8 coop with a 4x16 run. Is the coop size going to be big enough for when they chickens have reached their full growth? We are also, planning to build a chicken tractor so we can move them around in the yard to forage. Any advice would be great!