I have a 4x6 coop that advertised it's for 12-15 hens but at 4 sq. ft. per bird I would only be able to house 6 (24 sq. ft.). At 10 " roosting space per bird I could fit 14 birds and I have 6 nest boxes (outside of the 4x6 dimension). So is the height taken into consideration? How many should I really consider having. They have a large enough area for daytime.