I have 1 of my EE hens laying an egg with tiny clusters of little bumps all over it. I looked the picture up and everything points to not enough calcium, I put out oyster shell and crushed, cooked egg shells. I thought it would just correct itself, but were going on 2 mos now and it's not. We still eat the eggs but some of the shells are so brittle it breaks into pieces when u try to crack it open. Don't know if i can change the feed as the chickens, ducks, turkey's all go into each others pens and eat, but in the chicken pen I do have chicken crumbles and self serve oyster shell on the side, plus they free range all day.
You can also add the egg shells to the wet feed this is how I do it