Yep, and the thing is to keep oxygen
from penetrating the shell. That spoils them. So one way, as I mentioned is just to turn them over every few days - that way the egg inside coats the shell. I like that way because it's simple and not messy.
Other ways include putting vaseline on the outside of the shell, or water glass. Or boiling them just a wee bit to cook a thin film on the inside; but they all accomplish the same thing.
It's amazing what doesn't require refrigeration. But with produce (and eggs), once they've been refrigerated they tend to spoil a lot quicker without it.