I have a 5 month pullet that is already laying. She lives with 3 eleven weeks chicks. They are all on grower feed. I have a dish with oyster shells and crushed egg shells by the feed 24/7. I never see the pullet eating from the dish. I am concerned about the pullet not having enough calcium for the eggs. I have tried giving her dried grubs dusted in oyster shell powder but she won't eat them. Any suggestions to give her some calcium?