Egg eating can be because a hen needs the protein or the calcium or because it has become a habit. Once they get started it is hard to break them.
First, make sure your birds are on a good diet. Keep the treats down to 10% of the diet or less. Always keep oyster shell available at all times. And keep it near the food and water, they won't go looking for it.
Collect eggs often so they are not laying around to be eaten. Keep fake eggs in the boxes at all times. What this does is when hens go cruising for eggs after you have collected them, they go try to open these fake eggs and when they can't get in, over time this can help them from trying to get into the real thing.
Next, put curtains over your nest boxes. I had a terrible time with egg eating one year and this solved the problem completely...
This is an older picture and I have since added another thick layer. What this does is makes the boxes really dark inside. The hen slips in and lays her egg and because it is dark she doesn't mess with eggs. It also stops other hens from cruising for eggs. If they can't see them from the outside, they don't seem to want to mess with them.
But the key is to collect often at first. You need to break the habit. With these curtains, a good diet and oyster shell on the side, the desire to eat eggs will decline over time. Be diligent and you should be able to break them of this habit.
If you have a hen that is laying thin shelled eggs, these get eaten quite easily. You may need to give her some extra calcium. I had good luck with using "Caltrate" on an older hen that was laying thin shells and yolks. I broke one tablet in half and broke this half into pieces and put them in raisins. I gave her half a Caltrate a day for a while and she went back to laying eggs with shells on them. But these types of eggs need to be collected quick as these are the ones they go after.
