Because they know a good thing when they see it....but this does not mean you have "egg-eaters". As suggested, you may be having soft-shelled eggs that become easily crushed when other hens climb into the nest to lay, which they will promptly clean right up if they see the break and leakage.
I've fed my gals dirty and busted eggs for years and they have never developed into egg-eaters....but they do eat eggs when I give them or they find a broken egg. Check your egg shells for thin walls, provide supplemental OS and remember that during this time of year the egg-laying can get a little funky and you might see odd shaped, soft shelled, no shells, extra calcium deposits on the shells, etc. in your eggs. Birds are molting and a lot of their nutrition is needed for regrowth of feathers.
Try these things..... increase their protein. Give them hamburger or fish of some sort daily for a week and see if that helps. (I switched from 16% to 20% layer pellet.) Make sure they have free choice oyster shell just in case the shells are getting thin and are easier to break. Put fake eggs in the nesting boxes and collect eggs often. Make sure the nesting boxes are nice and padded so the eggs don't crack when they are laid. You can put a Flock Block out just in case it is boredom. Some have good luck with spiking the eggs with various tastes and spicy stuff although I have never done that. My egg eating was due to the protein issue and so now I feed the higher %. No more problems in my flock. Good Luck!