I have three hens over a year old. With them are two pullets that are about 13 weeks old. They all free range. Since adding the little ones, I moved them from layer feed to the starter/grower and have free choice oyster shell. Since moving them to the starter/grower, one hen has had some problems with thin and soft shelled eggs. She does great on layer feed but she's not eating the oyster shell and she needs to. She's always kinda had what I suspect as a kooky shell gland as her eggs would have a lot of calcium deposits on them while on layer feed. Anyway, does any advice?