I have some new layers, Black and Blue Copper Marans. One of them is giving me a beautiful mahogany egg that would grade really high on the desirable color scale but the texture of the egg shell is weird. Instead of being smooth it's a matt color and texture of the shell feels as though it was rolled in super fine sand. Does this seem like it might be a nutrition issue? Is she missing something in her diet? What do you think about this?