We are new to keeping chickens and are about to start building our coop and run. We want to put the walk-in coop up off the ground to allow the chickens to go underneath the coop for added run space. So we need to know how tall are adult chickens? We will have Buff Orpington, Cochin, RIR, EE, Silver Laced Wyandotte, Delaware, Dominique, Black and Red Sex Link.