Mine will do this at the end of the winter. Generally I up the protein to well over 20% and increase the amount of calcium. Within a few days the problem goes away. When I say I increase the calcium, I mean that I add it right into the feed instead of offering it separately. That way I KNOW they are getting it. If the egg eating is not well established, this will generally cure it, but occasionally a hen will just develop a taste for eggs. There is no cure for that except the rollout nest or the stew pot.
HTH
Rusty