Our pullets, 3 Leghorn, 3 Bard Rock and 2 RIR, are a little over 21 weeks old. No eggs yet although some of their combs are getting big and red, which I believe is an indication of laying time. We were told by BYC that we should continue to feed Grower/Finisher until we begin to get eggs. At that point we should switch to Layer. Doing it anytime sooner would be hard on their kidneys.... Are we correct in this information? My husband has me second quessing myself and wondering if we don't have eggs because of the feed. And btw, where do we get these ground oysters shells that everyone talks about? We get our feed at the local Agway. Would they carry this also?