After the Revolutionary War, Washington started a program to develop a larger, stronger mule to be used on farms. In less than fifteen years Washington had 58 mules working at Mount Vernon. In 1786, Washington advertised the “compound’s” services in a Philadelphia journal. The stud fee for serving horses was a third less than it was for serving donkeys. mules from Washington’s stock became the forerunners of mule and the backbone of American agriculture for generations.