My two hens are so funny! The insist on laying on rocks, concrete, or brick. They make a nice nest with straw or shavings , but the bottom of the nest is alway bare and hard. I have seen them put rocks into their nesting box. Every day has also become an easter egg hunt. It seems that after a couple of days in one nest, they move again. Anybody else have funny duck who insist on laying on a hard surface?