I have a batch of ducklings that are getting towards laying age (18 weeks). And another batch that are 7 weeks old. I have been feeding them a 20% protein ration (Purina Sunfresh Flockraiser). They free-range all day around and in a pond, too. I'm wondering if I can just keep feeding the same thing to all of them, and put a bowl of oyster shell out so that the laying hens have the extra calcium they need? Or will the younger ducklings (and the older drakes) eat it too? I'm not sure to what extent they self-regulate. I'd appreciate any advice, thanks in advance.