My husband built a few boxes out of scrap plywood for my brown layers. The leghorns have a lidded cat litter box. I don't really like the cat box one, simply because we have snakes in the area (found one in the brown egg nests) and it's much harder to see the entire inside of the cat box nest. My daughter helps collect eggs and I get nervous everytime she sticks her hand in there.
Over the summer, my DH and I are going to be redoing all the coops and nestboxes. The cat box will be reserved for broody hens after that.