A barn is an agricultural building used for storage and as a covered workplace. It may sometimes be used to house animals or to store farming vehicles and equipment. Barns are most commonly found on a farm or former farm.
Older barns were usually built from lumber sawn from timber on the farm, although stone barns were sometimes built in New England, U.S.A., and other areas where stone was a cheaper building material. Modern barns are more typically steel buildings. Prior to the 1900s, most barns were timber framed (also known as post and beam) forming very strong structures to withstand storms and heavy loads of animal feed. From about 1900 to 1940, many large dairy barns were built in northern USA. These commonly have gambrel, or hip roofs to maximize the size of the hayloft above the dairy roof, and have become associated in the popular image of a dairy farm. The barns that were common to the wheatbelt held large numbers of pulling horses such as Clydesdales or Percherons. These large wooden barns, especially when filled with hay, could make spectacular fires that were usually total losses for the farmers. With the advent of balers it became possible to store hay and straw outdoors in stacks surrounded by a plowed fireguard. Many barns in the northern United States are painted red with a white trim. One possible reason for this is that ferric oxide, which is used to create red paint, was the cheapest and most readily available chemical for farmers in New England and nearby areas. Another possible reason is that ferric oxide acts a preservative and so painting a barn with it would help to protect the structure.
With the popularity of tractors following World War II many barns were taken down or replaced with modern Quonset huts made of plywood or galvanized steel. Beef ranches and dairies began building smaller loftless barns often of Quonset huts or of steel walls on a treated wood frame (old telephone or power poles). By the 1960s it was found that cattle receive sufficient shelter from trees or wind fences (usually wooden slabs 20% open).
In older style barns, the upper area was used to store hay and sometimes grain. This is called the mow (rhymes with cow) or the hayloft. A large door at the top of the ends of the barn could be opened up so that hay could be put in the loft. The hay was hoisted into the barn by a system containing pulleys and a trolley that ran along a track attached to the top ridge of the barn. Trap doors in the floor allowed animal feed to be dropped into the mangers for the animals.
In New England, it is common to find barns attached to the main farmhouse (connected farm architecture), allowing for chores to be done while sheltering the worker from the weather.
In the middle of the twentieth century, the large broad roof of barns were sometimes painted with slogans in the United States. Most common of these were the 900 barns painted with ads for Rock City.
A farm often has pens of varying shapes and sizes used to shelter large and small animals. The pens used to shelter large animals are called stalls and are usually located on the lower floor. Other common areas, or features, of a typical barn include: