My girls are growing up and I need to think about what I'll be feeding them in the coming weeks. This is my question: I understand that layer feed has the added calcium for chickens who are laying eggs. But if I am supplementing my hens with eggs shells, oyster shell, etc, do I even need that or can I just give them a general feed without calcium? Also, if I do give them layer feed, do they still need supplemental calcium on top of that? Thanks a million!