I converted a rabbit hutch for our chicks (4 and 5 weeks old) and after reading about sweet pdz, decided to make trays on the floor filled with it. Sounds great and looks nice, but they won't walk in it! All four have stayed on top of feeder for the last 24 hours -- except when we moved them ourselves, but they did everything they could not to walk in the stuff. I put their water and a treat at the opposite side, but even that didn't coax them off. In fact, it's pretty hot and humid here so we finally put the water where they could reach it from the feeder. Didn't want to be an enabler, but didn't want dead chicks, either.
I put a roost near the top of the coop made out of a PVC pipe, but I'm thinking its too slippery and maybe not sturdy enough. Today I added a branch across the floor so they can get the idea. If they get brave enough they may just use it to walk from one end to the other without touching the floor!