In one century a lot has changed. Forty years ago special breeds of horses started pulling plows instead of oxen. Farmers are getting horses that are healthier, heavier, and stronger. People shipped horses from Europe to farmers in America. Farmers selectively breed their horses to create strong draft animals. In Hadley, around 1900, steam-powered tractors were introduced to farmers. In about a 10-year period, things will change drastically for animal life on the farm.