An animal pound is a place where stray livestock were impounded. Animals were kept in a dedicated enclosure, until claimed by their owners, or sold to cover the costs of impounding.
North Elmham village pound, Norfolk
The town pound of Glocester, Rhode Island in New England, US, c. 1748
Capenhurst pinfold, Cheshire. A pinfold has existed on this site since the 10th century.
Circular village pound in Stanton Prior, Somerset. (Above the pound are hot-air balloons taking off from Bath (6 miles or 9.7 km to the north-east.)
A pen is a fenced/walled open-air enclosure for holding land animals in captivity, typically for livestock but may also be used for holding other domesticated animals such as pets that are unwanted in
Animal pound
…Kraal Pen (enclosure) Scarisbrick, Lancashire, in which is the hamlet of Pinfold…
Sheep in a pen, in Yorkshire, England
Pen for goats in Macedonia
Sheep near a dry stone sheepfold, one of the oldest types of livestock enclosure
Folding portable wire exercise pen