PART II: OUTDOOR PIG PRODUCTION METHODS
9. Since the domestication of pigs, outdoor systems have been an important part of pig production. As far back as the 9th century, pigs were reported to be kept in large groups to scavenge for food in the forests. In the 18th century, the increase in population and the enclosure of land encouraged greater control over pig production. This led firstly to the cottager's sty and eventually to the intensive housing based industry we have today.