Little pitchers have big ears

Has anyone heard the origin of the saying: "Little pitchers have big ears"??

LITTLE PITCHERS HAVE BIG EARS - "Children hear and understand more than you think they do. The play here is on the resemblance of the ear to the handle of a pitcher. It is an ancient saying, having been recorded by John Heywood in 1546: 'Auoyd your children, smal pitchers haue wide eares.'" From The Dictionary of Cliches by James Rogers (Ballantine Books, New York, 1985).