After our winter egg laying hiatus, one of our three chickens failed to start with the onset of spring light. I was beginning to worry she might be egg-bound, but there seemed to be no other obvious ill effects on her health. Finally, about three months after the other two had started laying, she laid her first egg ... as it turned out it was the first I'd found intact, not necessarily the first laid. All of the eggs she lays are very thin shelled now and fracture (crush) easily. Many had crushed into their straw nesting material. In previous seasons (this is our fifth with these chickens) "Elaine" always began laying around the same time as our other two and her eggs have always been just as stout. I feed them laying pellets that include calcium and supplement with crushed oyster shell, a good cracked corn and seed scratch, and include flax and safflower seeds. They also get bugs and such from the yard. Presently our other two chickens are laying their typical eggs, (practically needing a hammer to open them) and they and "Elaine" seem absolutely healthy in every other way. A final datum: "Elaine" (the thin-shell layer) is a 'Plymouth', or 'Barred Rock'; the other two are a 'Rhode Island Red' and a 'Buff Orpington' Any and all input/ideas will be greatly appreciated.