My husband kept chickens as a child and he apparently used old coke crates from a store his dad worked at and his chickens laid fine. He is busy building our chicken house as we speak but hasn't built actual nest boxes into the design. I was wondering if a whole box with a roof and all was really 100% a must have for them to lay. Operating on the idea of him using shallow crates I was wondering if meduim sized litter boxes like the cheap-o's you can get a walmart would do the trick. We have several of those that have never been used for the cats. I use them from time to time for washing the furnishing and skirts on my dogs at shows but really don't have anyone who requires that anymore. Anyway we have extras and want to know if the chickens could use them.