18 to 24 inches off the ground.....mine are about 48 inches....but they need a ladder to get up and down from there...
chickens like to roost up high...it makes htem feel safe!
ipie there really is no "proper" height for roosts. Ours vary from 3 feet at the lowest to 6 feet for the highest one. Like Goldie we have a ladder for ours to get up there. I've seen photos on here of chickens way up in the barn rafters.
I will say that heavy chickens need roosts lower down . Chickens will use a ladder to get up at night but always seem to fly down. If the roosts are too tall for the heavier chickens they can hurt themselves jumping/flying down.
I have roosts starting 18 inches off the floor all the way to six feet. Most of my adult birds choose to sleep in the seven feet high rafters
. They use the bottom three roost as ladders to get higher, but don't sleep on them. I also have a few stubborn chickens that sleep on top of my nest boxes.