Welcome to BYC and the coop! There's a lot of great peeps here! Feel free to ask lots of questions. But most of all, make yourself at home. I'm so glad you decided to joined the BYC family. I look forward to seeing you around BYC.
I don't have any oaster shells around but will get some. My youngest layer is 6 months I'm thinking it's her. also, I just introduced scratch to my feed they have been on laying pellets and fruits and veggies. I'm certainly going to read the page you recommended thank you.