Sometimes when I go to collect eggs I find that one of the hens has eaten or is eating one of the eggs. The vet says its because of a calcium deficiency, so we mixed crushed oyster shells in with their feed but they won't eat it! they will seriously pick the oyster shells out & not eat them! So I don't know what to do! I can't let them keep eating the eggs but they just WON'T eat the shells! Any Advise???????????? Thanks!