Have several breeds of black pullets. All are 4-5 weeks old. It is time to move the fully feathered youngsters to their new homes. Problem is-at this age how do I tell the black minorcas, black australorps and black giants apart? They are all so...........well black! actually I only really need to be able to tell the giants from the others-the others go to the same place. the giants are mine. any hints?