Sometimes they want protein, and other times they do it because it tastes good. I feed my chickens their eggs. If there are ten eggs that day, I give them like two. I would give them more, but my family wants to eat them. I just toss them on the ground and they love it. So, I am not the one to tel you how to break an egg eater, because I am of the mindset that they lay the egg, and it is theirs, so they can do what they want with it. Typically mine do not eat their eggs unless I give it to them anyways.
If it's not a low calcium problem, your hen may just not be a very good layer - that happens sometimes.
