We have three Barred Plymouth rocks and 3 Golden Comets. They began laying on January 14th. We've gotten at least one egg each day since, and as many as 4. They are all smaller than grocery store eggs, but sooo much better. How long does it take for them to increase to full size? The golf ball worked! The large egg was a double yolk! First two eggs. Size comparison with a grocery store large egg in the middle. Double yolk on the right, grocery store egg in the middle.