I have a pair of aprox. 7 week old cuckoo marans pullets. They are probably sisters, but I don't know for sure. When they arrived at about 1 week old they were identical in size an appearance, but at this point one of them is easily twice the size of the other. The little one is eating and drinking and looks healthy, but she is just so tiny that I wonder if I should be doing something extra for her as far as nutrition is concerned. Any advice?