But Sylvester, you are ignoring the fact that some coop manufacturers stick WAY more nest boxes in the coops than the coop can properly hold in chickens. Coopmaster's coop is a recent example. 6x8 bird space = 12 chickens but there are 16 nest boxes. Given that 4 birds will easily use one nest box, the coop could accommodate 48 hens ... as long as 3/4 of them live somewhere else
I would go with - Measure the floor area. Subtract any square footage that is under something less than 18" high. That includes roosts, nest boxes, feeders and waterers. Divide the remaining area by 4. That is the number of chickens the coop can house AND there must be at least that much lineal footage of roosts.
IF and ONLY IF your chickens are NEVER locked in the coop except when they are asleep, you can get more birds in if you have the roost space.
Coop floor space is 4' x 8'. No roosts or anything lower than 18". 6 nesting boxes that are 12" x 12". Front wall is 7'6" tall back wall is 6'2" tall. Front wall has full size man door and a 36" x 36" window. We are planning 5 - 6 hens.
Edited by timothyyoung - 3/29/16 at 5:15pm