A pen is an enclosure for
domestic animals. Most common types of pens are
pigpens, horse paddocks, cattle pens, and sheep pens. A large pen for horses is called a paddock (USA, UK) or a corral (Western USA), a borrowing from the
Spanish language. A small pen for horses (no more than 15-20 feet on any side) is a stall if inside a
barn or
stable, or simply a "pen" if it lacks any roof or shelter. The term paddock is sometimes used interchangably with
pasture in Australia.
See more at Wikipedia.org...