Yes. I mean eggshells. You can only give just egg shells over and over again without any other form of calcium before they are no good. Having another source of calcium plus egg shells is fine. But the point of eggshells is to give calcium back to the chickens. Which if you don’t supply another source of calcium the shell will become weak and eventually be shelless. Their bodies can only supply so much calcium before it just won’t. Which in turn means less and less calcium in the shell.
Wait, what??? Do you mean eggshells?
I don’t know if you knew all that but if so I’m sorry for going into so much detail.