Free: Contests & Raffles.
Duck tractor!
For my first pen I put sand over d1 grave with porous weed cloth betweenl. It just ended up turning into poop cemented sand. Drained ok for a few months but that was it. I actually built it up above ground level inside the pen about 4", not great but better than a Jud pit. If you cleaned the sand every few months it would work ok.