More common would be silos - round buildings used for storing feed and grain.
http://travel.webshots.com/photo/1119412736049760384HCgRiq
The silos have actually informed American architectural design:
"In Normandy, silos were often attached to the main living quarters instead of a separate barn. After World War I, Americans romanticized the traditional French farmhouse, creating a charming French Country style known as French Normandy. Sided with stone, stucco, or brick, these homes may suggest the Tudor style with decorative half timbering (vertical, horizontal, and diagonal strips of wood set in masonry). The French Normandy style is distinguished by a round stone tower (the silo), topped by a cone-shaped roof."