Justin Rhodes large chicken chicken tractor. Don't build it (which was a pain) just buy it. You probably can't build this now for what you pay for it. Flat free tires. Never clean poop. Easily holds 40 chickens. Easy to move. I had a rollaway nest box on the back but you can easily add 3 to 4 crates for nesting boxes. Predator-Proof and built to last. Easily add an automatic door for convenience.