I watched her do it today and non of them peck at it (i set up a camera to see just cause) and i found out that she does not squat down to lay it she just lays it. So they don't peck it the force to ground is what dents it. At least their not egg eaters, lol.
I haven't seen a hen lay while lying down; they all stand at the end, in my experience.
If your eggs are truly healthy they should be able to tolerate dropping from 6 feet onto the soil, never mind an inch or two; in fact they can tolerate being repeatedly slammed into the ground, thrown a hundred feet and bouncing off rocks, trees etc... They can actually be hilariously hard to break.
I suspect, going from what you're saying, your other hens are laying good eggs but this hen is laying weak ones and has learned she can eat them precisely because they break under situations that would not break normal eggs.
Chooks soon learn that not all eggs are equal, given a chance, and will make a habit of tapping all eggs to see which break open. From there it doesn't take much for them to learn that sufficient force breaks any egg; the sharp, small surface area impacts that beaks cause are something eggs can't tolerate anywhere near as well as blunt large surface area impacts like hitting the soil or a nest.
Will their beaks grow back thought?
Yes, second last line of my previous post confirmed that; they grow back quickly, just like spur tips and claw tips.
You'd have to cut into the quick to stop it growing so fast, which is inhumane and obviously not something I'd recommend.
Thanks
You're welcome, best wishes with them.