I am working on plans to build a bigger coop to add more chickens to the flock, that and the coop that I was given is much too small for the 4 older girls that it came with (2' x 3' x 3' tall). Looking to add 4-6 more chickens. Currently planning on an 6-8' long x 3' wide coop with a 3' back wall and 4' front wall. The nesting boxes will be built on an exterior wall so as not to take away from internal space. It will be on risers with a 2'-3' tall run underneath and attached to a 16'long x 4'wide x 6' tall run with access to a 28'x28' garden to free range in occasionally. They will have permanent access to the attached run from 5am-9pm. The gravity feeder and waterer are located in the run. Will the 3'-4' tall inside height be sufficient for roosting? Eventually they will have full access to the 28' x 28' garden area once netted and fenced off.