Well seeing that my chickens are all about 13 weeks old I thought I shoud put a pair of nesting boxes in the coop. They are stackable crates from Walmart. I put a waterproof layer on the bottom of each crate before filling it up with bedding. Thought that should work. First things my brats did was pull the layers and all the bedding from the crates as soon as my back was turned. What should I do now?