I have used 2x4 untreated and two concrete blocks. My chickens loved them. You would not think it, but they like taking a break from balancing once in the while. The only reason they aren’t on them at night now is we took their box out and need to build another. I also have tree branches for daytime roost.
I tell you, I quickly found solutions for bumblefoot.
My nests are 1 ft off the ground.
My branches have branches to climb down rather than jump.
Their night time retreat is on the ground.
Luckily.. I don’t have any issues since bringing everything down to their level.
I also use pea gravel mixed with Oak leaves to keep their nails, feet, and crop clean.