We have 10 chickens in our coop, 6 red sex linked and 2 white leghorns. We have four girls laying. They were always laying in their nesting boxes. Every once in a while we would find an egg on the coop floor crushed when we opened it up in the morning. It is getting more frequent. Does anyone have any thoughts why? We have four nesting boxes but the girls only use two of them. Its very frustrating to lose eggs like this, any input would be appreciated!