I have a dozen new Australorp pullets. They are approx 16 weeks old and I am feeding them with Chick Grower. They are doing very well. How long should I keep them on the Grower? When should I change over to pellets? What is the best feed to give them? The man I purchased these pullets from told me that I should keep my chooks locked in their pen every second day and give them a feed of pollard mixed with dolomite. He told me that this would prevent the egg shells from becoming brittle as the hens age. Has anyone ever heard of such a practice? Would it be safe to do as he suggests?