One of my five hens (all the same age) just recently laid her first egg!!She's the only one laying at the moment. I put out some oyster shell for her to have if she feels the need. I've been assured the other girls wouldn't touch it. However, I've noticed ALL of them eating it! Does anybody have any idea why the girls who aren't laying yet would be eating the calcium? Are they just maybe getting close to laying and need it? ??