wrathsfarm
*this space for rent*
I'm talking average sized birds. If this stacked set up is for a bantam coop it could possibly work great. Of course your nest boxes don't need to be tall either so that lowers your roost height also.Brooders need to be just tall enough for a hen to be comfortable standing up. I don't know any average heights of Bantams so can't help there other than they're small.
Really there's no set height other than you want your roosts higher than your nest boxes to deter sleeping in them.
Another thing to consider especially if your doing brooder/nest boxes/roosts all stacked is that's pretty high and consider when they fly down at that angle they need the floor space to land without hitting a wall and think about aging birds and they're limits. This may not be an issue if your building a small bantam brooder but it would if say you have a large bird that unexpectedly goes broody, now this brooder is too short.
My 2 brooders in the Marans coop are 22 1/2" tall to the bottom of the poop boards, but I hadn't planned on building them when I built the poop boards/roosts, they were just a quick... "I need brooders now".