A battery hen is a bizarre machine built by Doctor Robotnik. In the Issue 42 story A Day in the Life of Robotnik, this machine was seen producing eggs. These eggs are created inhumanely and probably have no 'real' egg in them at all. They are then taken to Robotnik by a Mantis Badnik (who doesn't care for the hen's complaining). Robotnik has these artificial eggs for breakfast every day. He even stores various sizes of egg in boxes all around his dining room.