I have been leaving a pile of girt for the treats the girls get and have been feeding them medicated starter feed, but now they are getting to be laying age - still waiting for the first little present . I also have grown Guinea males who share the space and they get into each others feed. SO I'm thinking I want to just provide flock raiser, but put some oyster shell in the coop for my ladies. but do they also need grit or would Oyster shell provide the benefits of grit? Does this seem like a good plan to all you wonderful, wonderful experts out there? Thanks.