We recently built a simple chicken tractor to keep our four girls safe while they roam (we have cats, dogs, owls, eagles, hawks, racoons, coyotes, and foxes...after almost losing one hen it was too much for me to stress about!). They spend the night in a stationary coop. However, 2 of my girls lay in the afternoon, so I needed a portable nest box to go in the tractor. Inspiration struck and I put an old covered cat litter box into service. It is just the right size, comfy when full of shavings, light and easy to carry by the handle on top, and easy to clean. The girls took to it right away. Hopefully this helps someone else out too!