I've put 12 six week old birds in with my 8 one-year old hens. I put them in a second coop and run adjacent to the first, then two weeks later removed the fence between them, allowing free access across both coops and runs (and both feeders and waterers). This plan has worked marvelously to get both flocks integrated with almost no quarrelling. But now I wonder about their food - the feeder for the young birds has starter feed, while the older birds' feeder has layer feed. But because they're all getting along so well that they're all eating eachothers food. Should I just leave well enough alone? Thanks!