I've had them start at egg eating in the past. What worked for me was to change nest boxes completely, cutting off or removing access to the old one, and replacing it with a totally new box that was barely big enough for the hen to sit in the lay. Mount the new box between 3 and 4 feet off the ground, and in a place with some light. Put some clean straw in it and keep it clean. Be sure to gather the eggs regularly, as many times a day as you can, so they aren't sitting there being a temptation. They need to disassociate the nest box and eggs with "something yummy".
Make sure they NEVER run out of food or water, and make sure they have access to high calcium grit. Try upping their protein -- use something like a turkey grower for a week or so, rather than just 16% layer pellets. Give them as much other stuff to eat as possible, such as table scraps, greens, etc.
I hope this helps. That approach has worked for me in the past.
