Since the mid-20th century, small, extensive farms have given way to massive, commercial pig production facilities. In 2009, more than 1.3 billion pigs were raised and slaughtered globally. Between 1980 and 2000, though world pork production nearly doubled, there was a decrease in the total number of farms. Large industrial farm animal production facilities, or factory farms, that often confine thousands of pigs indoors, are becoming more widespread throughout the world, particularly in developing countries. Factory farms are now responsible for more than half of all global pork production.
A significant implication of the shift toward factory farms has been the “movement of large numbers of animals from pastures and open-air lots into confined spaces with no grass or vegetation for grazing.” Factory farms may have particularly severe implications for animal welfare, including the intensive confinement of farm animals in enclosures that prevent them from moving comfortably or expressing most basic natural behaviors. Around the world, millions of breeding sows (female pigs) in industrial systems are confined in 0.6-0.7 m (2.0-2.3 ft) by 2.0-2.1 m (6.6-6.9 ft) gestation crates for nearly their entire lives. These crates are about the size of the animals’ bodies, denying the sows the ability to exercise, turn around for months on end, or perform other integral, instinctual, and natural behaviors, including rooting, foraging, nest-building, and grazing. In addition to causing tremendous animal suffering, factory farms degrade the environment and negatively impact public health and rural communities.
Humane Society International, "An HSI Factsheet: The Environmental, Public Health, and Social Impacts of Pig Factory Farming" (2014). HSI Fact Sheets: Farm Animal Protection. Paper 5.