Roost height for a small coop?

[NicGotChicks]

My coop is 4'x4' (with an additional 18" off one side to accommodate the nesting boxes), the roof slopes so the height changes along with the roof. The highest height is 36" and then it slopes down to 27".

All that being said, how tall should my roost be off the ground? I want them to roost, rather than sleep on the floor or in the nesting box, but I don't want them bumping their heads when they jump off.

I have 3 Wyandottes, btw

Thanks!!

 

[jetdog]

The roost should be a little higher than the nest boxes, they will always goto the highest level they can, don't worry about them bumping their heads they will be able to hop that high with no problem, if your worried you can build a small ramp up to the roost, mine have a ramp but would rather fly up.