I have been reading about when to offer oyster shells to young birds. Several people say to only start feeding layer feed when the first eggs appear. Others suggested to put it in a separate container, so they could just take it when they need it. My girls (at least I hope they are girls) are 18 weeks, and doing well but not laying yet. When I saw people posting the first eggs coming at 18 weeks, I decided to put in a small corner feeder with oyster shells. I read that it can cause internal issues if fed too early, so when my 5 chickens went wild and started eating it like crazy, I took it out. I would appreciate any advice you can give. Thanks!