An animal stall is an enclosure housing one or a few animals. Stalls for animals can often be found wherever animals are kept: a horse stable is often a purpose-built and permanent structure. A farmer's barn may be subdivided into animal stalls or pens for cows and other livestock.
Animal stall Wikipedia
In horse care, the standard dimensions for a "loose box" (UK) or "box stall" (US) vary from 10 by 12 feet (3.0 by 3.7 m) to 14 by 14 feet (4.3 by 4.3 m), depending on local cultural traditions, the breed of horse, gender, and any special needs. Mares with foals often are kept in double stalls. Stallions, kept alone with less access to turnout, are also often given larger quarters. Ponies sometimes are kept in smaller box stalls, sometimes as small as 8 by 8 feet (2.4 m × 2.4 m), and warmbloods or draft horses may need larger ones. Box stalls usually contain a layer of absorbent bedding such as straw or wood shavings and need to be cleaned daily.
Prior to the late 20th century, the tie stall or standing stall was a more common housing for working horses that were taken out daily. Taking only half the size of a box stall, more animals could be housed in a single barn or stable. Generally about 5 by 10 feet (1.5 by 3.0 m) or sometimes smaller, with a manger in the front, usually to which the animal was tied, the design allowed the horse to lie down if the lead rope was long enough, but not to turn around.
A stall for milking cows is also called bail. The latter term is also used for other semi-enclosures, such as for livestock feeding.