We got our first egg today! It was either an Orpington or Barred Rock who laid it, but it really doesn’t matter to me. My question is whether or not I have to switch to layer feed if 1/7 hens is laying and whether or not to introduce oyster shell. I have grit in their run at all times, does oyster shell have to be separate from grit, or is it instead of grit? They’re all 24 weeks (DOB 6/7)