Honestly, I just have a treated 2x8 that is 6 ft long.... It goes up to two feet above the ground..... And that's all it is, a 2x8.... They seem to like it just fine and have no stability issues.... But is a very small grade anyway...
I made a ramp using hardware cloth to see if it would be easier to keep clean. It is much easier to clean. The chickens didn't like it at first, but took to it after a few days.
Coolcanoechic
Try laying down a thin layer of hay when the chicken r gettin used to it. They will eventually scratch it all away an then be conforatble walking on it