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Pig factory farming

Updated: Jun 8, 2022

Intensive pig farming, also known as pig factory farming, is the primary method of pig production, in which grower pigs are housed indoors in group-housing or straw-lined sheds, whilst pregnant sows are housed in gestation crates or pens and give birth in farrowing crates.

The use of gestation crates for pregnant sows has lowered birth production costs; however, this practice has led to more significant animal cruelty. Many of the world’s largest producers of pigs (US, China and Mexico) use gestation crates. The European Union has banned the use of gestation crates after the fourth week of pregnancy. Intensive pig farmers often cut off tails, testes or teeth of pigs without anesthetic.

Globally, mother pigs are reared in intensive, barren factory farms where they are confined in steel cages – sow-stalls – for their entire pregnancy. In factory farms, piglets are taken from their mothers at just three-weeks of age. 

Pigs are highly intelligent, charismatic and social animals. They have the cognitive ability to be quite sophisticated. Even more so than dogs, says Dr. Donald Broom, a Cambridge University professor and a former scientific adviser to the Council of Europe. Pigs can play video games, and when given the choice, they have indicated temperature preferences in their surroundings.

These facts should not come as a surprise to anyone who has spent time around these social, playful animals. Pigs, who can live into their teens, are protective of their young and form strong bonds with other pigs. Pigs are clean animals, but they do not sweat as humans do, so they prefer cool surfaces, such as mud, to help regulate their body temperature.

On any given day in the U.S., there are more than 75 million pigs on factory farms, and 121 million are killed for food each year.

Sows suckle their litter of piglets in the farrowing, or birthing. Original image from Carol M. Highsmith’s America, Library of Congress collection.

The majority of mother pigs (sows)—who account for more than 6 million of the pigs in the U.S.—spend most of their lives in individual “gestation” crates. These crates are about 7 feet long and 2 feet wide—too small to allow the animals even to turn around. After giving birth to piglets, sows are moved to “farrowing” crates, which are wide enough for them to lie down and nurse their babies but not big enough for them to turn around or build nests for their young. Once her piglets are gone, the sow is impregnated again, and the cycle continues for three or four years before she is slaughtered. This intensive confinement produces stress- and boredom-related behavior, such as chewing on cage bars.

Confined pigs, pig farm, West Bank / Photo credit to Kim Bartlett - Animal People, Inc.

After they are taken from their mothers, piglets are confined to pens and barns over the span of about six months, fed until they weigh upwards of 280 lbs and are ready to be sold as meat. Every year in the U.S., millions of male piglets are castrated (usually without being given any painkillers) because consumers supposedly complain of “boar taint” in meat that comes from intact animals. Piglets are not castrated in the U.K. or Ireland, but the practice varies in the European Union from country to country.

In extremely crowded conditions, piglets are prone to stress-related behavior such as cannibalism and tail-biting, so farmers often chop off piglets’ tails and use pliers to break off the ends of their teeth—without giving them any painkillers. For identification purposes, farmers also cut out chunks of the young animals’ ears.

Early weaning leaves the piglets with a weakened immune system and makes them susceptible to disease and infection. Because of this, routine antibiotics are used to prevent disease in the overcrowded conditions associated with industrial scale farming. In the UK, approximately 50% of all antibiotics created are used for agriculture and 64% of this total are used on pigs as they are often in more crowded conditions than other animal factories. Concerns arise when humans begin to show antibiotic resistance to once effective medicines, putting us all at risk of serious harm from conditions that were once treatable.

In addition to this, the large number of antibiotics ingested by pigs creates another issue. Pigs produce ten times as much fecal waste as humans so with thousands of pigs in one shed there is a lot of waste to consider. In some countries, pig waste is sprayed on agricultural fields. Although animal manure has been used for millennia as fertilizer, spreading waste from animal factories is not quite the same. This waste is full of antibiotic resistant organisms and the quantities are too vast to be useful to any farmer’s field. When the ground becomes saturated, the waste either leaches through to the ground water or runs off into local lakes and streams. The high levels of nitrogen can also lead to algae blooms in the water system suffocating aquatic life.