Good to know! Thanks, Aksmama.
I just went out and found 2 perfect eggs, still warm and lovely, very dark shelled, both laid by the same chicken, I think.
This is a relief to me, because I was afraid she was deficient in calcium, but if she can lay two eggs in a row, both with perfect shells, that is a very good sign?
A woman suggested I feed them a bit of ground flax to help eliminate any sandpaperishness to the shell, and sure enough, 2 days in to feeding flax to them, the eggs are perfect again! I had gotten one a couple of days ago that was a bit rough on the end (not the scratched type, but a bit bumpy and perhaps brittle), and the flax really did seem to help get rid of that. Or maybe it was the kale I started giving them (calcium in it)? Or the combination. Whatever, it was, it worked! I'm sure the free-ranging didn't hurt, either.
Clare