My standard breed hens are on Kent Home fresh 16 layer feed. The owner of the Kent store here told me I don't need oyster shell. So I haven't given it. Should I still offer it to them free choice in a separate container? We have had 6 or 7 soft shells from 20 week old birds....BUT, I believe those have all been first time eggs as they are all dropped from the roost or on the ground at first light. Only good eggs have been laid in the nesting boxes by the birds that are regular now and know what to do. See my reason for concern? Lot of soft shells for first egg...could that be an indication calcium is a little low?