My Light Brahma has been laying since Aug., but still is producing eggs with thin shells. There is a shell, it's just not nice and dense like everyone elses. I give them oyster shell in thier feed. Maybe she doesn't eat enough of it. Today and egg from her was broken in the nest box. It looked as if it broke when she was sitting, not pecked open. Do some hens just take a long time to get nice dense shells, or should I be doing something to help?