Pig Farming

Worldwide, around 1.4 billion pigs are bred, raised and slaughtered every year, and the numbers are rising. Much of this phenomenal growth is in China, which rears around half of the world’s pigs. The other big players are the EU, North America, Vietnam and Brazil.

The vast majority of pigs are factory-farmed. All live truly miserable lives. If we did to our dogs what pig producers are legally allowed to do to pigs, we would be prosecuted for cruelty. We would receive hefty fines. We might go to prison.

A Change of Heart

Bob Comis had been raising animals for slaughter for 10 years but the process began to weigh on his conscience….

Despite knowing that his career and diet were socially acceptable, he felt pangs of intrinsic guilt. He wrote, “As a pig farmer, I live an unethical life shrouded in the justificatory trappings of social acceptance.” He went on to question, “How can you justify taking a life for gustatory pleasure?” This internal tension eventually led him to convert his pig farm into a vegetable farm and adopt a vegan lifestyle. His story is so compelling that a documentary titled “The Last Pig” was made about his experience. He has since continued speaking out for animal rights, including his article detailing the cruel reality of “humane slaughter.”

Read about other farmers who recognise farm animals as friends, not food.

Pigs are intelligent and naturally affectionate. Their physical resilience (like most animals) allow them to survive in the terrible conditions forced upon them in a typical factory farm, however emotionally they cope poorly. It is common to see sows behaving in a stereotypical manner, licking the bars of their iron stalls, moving their head from side to side for hours on end.

Pigs are sociable animals. They thrive in stable social groups which typically would consist of a few sows with their young. In natural conditions, they will range over hundreds of kilometres and spend much of their day foraging and rooting for food. They will make nests to sleep in and they will dig out wallows in the mud when they need to cool down. They will eat small animals if they can catch them, but mostly they will forage for leaves, grass, roots, fruits and flowers.

On a factory farm, the breeding sows are typically in solitary confinement in narrow crates (known as sow stalls). Essentially, they are metal cages. Sow stalls deprive pregnant sows of almost all their natural behaviours in that they cannot exercise, explore, forage or socialise. A factory-farmed sow will never see the light of day, apart from her last day, when she is transported to the slaughterhouse. Sow stalls are illegal in Sweden and in the UK and are being phased out in a number of countries, but there is a long way to go before we see the end of this cruel confinement.

On a factory farm, a heavily pregnant sow is moved to what is known as a farrowing crate (this is nothing more than a very small cage). Bars keep the sow out of the piglets’ lying area to prevent crushing. A sow in natural conditions will build a nest for her young, however this option is not available to her in a crate. Piglets are weaned and taken away from their mother when they are 3 to 4 weeks old.

There is no rest period for the over-worked sow on a factory farm. Within a couple of weeks of weaning, she is inseminated again, usually artificially, and she will begin a new pregnancy. She will typically give birth to 10 – 12 piglets approximately twice a year. She will be forced to breed in this intense, unnatural manner until she is about three years old, at which stage she will be ‘spent’ as a high-performance breeding sow and she will be sold for slaughter. Farrowing crates are illegal in Sweden, Norway and Switzerland. They are widely used everywhere else.


On a factory farm, the pigs to be fattened for slaughter are raised in large groups in overcrowded pens, on concrete floors without bedding. They are often mutilated, having their tails docked and their teeth clipped or crushed. The latter procedure is to prevent the piglets from damaging their mother’s teats, while the former procedure is to eliminate the biting of other pigs’ tails. Both procedures are painful and are usually carried out without the use of anaesthetic. Because pigs are mixed with unfamiliar pigs, there is much conflict and stress. Most male piglets in Europe (not in the UK or in Ireland) are castrated shortly after birth. The scrotum is cut with a scalpel and the testes are pulled out and cut off. This is often carried out without the use of an anaesthetic.


Pigs are notoriously bad travellers, and they are especially vulnerable in hot and humid conditions, as they do not have sweat glands.


No animal reacts well to the slaughterhouse and pigs are no exception. In fact, they possibly suffer more than other animals on account of their heightened sensitivity to the slaughterhouse environment. It is not uncommon for pigs to die before they get to slaughter as a result of stress and trauma.


The total number of pigs in Ireland in June 2019 was estimated at 1,616,000 with 1,472,700 non-breeding pigs and 143,300 breeding pigs. The estimates are based on returns from the June 2019 Pig Survey which collects data on pig numbers held by specialised producers. Specialised pig farms, totalling 289, were included in the survey for June 2019, accounting for 88% of the estimated total pig population.
[CSO statistical release, 10 September 2019]

Over 99% of Ireland’s pigs are bred and reared in indoor, non-straw bedded, slatted or solid floor systems, often in units of over 1,000 pigs, with over 40% of the pig population living in units of over 10,000 animals.

According to the latest pig survey completed by the Department of Agriculture, 45% of total pig production in Ireland is accounted for by just 47 farms. The Landrace and the Large White are the dominant breed of pig in commercial production in Ireland.

Approximately 500,000 pigs are exported live every year from the Republic. The vast majority of these go to Northern Ireland for slaughter. Female pigs are exported live to Spain and to Italy for use as breeding sows.


There are alternatives to the intensive system of pig farming.

  • There is the higher welfare indoor system, where pigs are raised on solid floors with straw and other bedding material. The best of these systems allow for some degree of foraging and some degree of comfort.
  • There is the outdoor system, where there are no sow stalls or farrowing crates, where sows sleep in straw-filled huts, have access to an outdoor environment, and can act out natural behaviours such as nest building, rooting, wallowing and foraging. In most of these systems, the piglets are weaned and brought indoors to be raised indoors.
  • An extension of this system is where the piglets are born outside and spend half their lives (approximately three months) outside.
  • Finally, there’s the free-range system, where sows and their young live out their entire lives outdoors. The piglets typically spend up to eight weeks with their mother in these free-range and organic systems.

Swine flu occurs in people that are in contact with infected pigs. Symptoms are similar to that of regular human influenza and can include fever, lethargy, lack of appetite, coughing, runny nose, sore throat, nausea, vomiting and diarrhoea.

In 2009, the H1N1 swine flu pandemic killed an estimated 151,700 to 575,400 people globally. African Swine Flu (ASF) is harmless to humans but in pigs and wild boar, the fatality rate is almost 100%.

Scientists have likened pigs to ‘mixing vessels’ for generating pandemic influenza viruses because they host both mammalian and avian flu viruses. When different strains of a virus occupy the same animal, they can swap genes to create new strains with the potential to infect new hosts. Research led by Honglei Sun at China Agricultural University (CAU) in Beijing has identified such a strain in pigs that has already begun to infect humans. Called G4, it incorporates genes from three distinct influenza strains:

  • a strain similar to viruses present in European and Asian birds
  • a North American strain that has genes from avian, human, and pig influenza viruses
  • the H1N1 strain that researchers first detected in the United States and that caused the 2009 swine flu pandemic

In the UK, the average sow produces 25.8 pigs a year. In the US that number rises to 26.4. But in Denmark, the world’s laboratory for industrial pig farming, the average sow produces 33.3 piglets – and some farmers manage to push that figure even higher. Some believe that one day they could reach the magic number of 50. These high performing sows do not last long. After delivering just three to four litters they are sent off in large numbers to the abattoir. Danish pig farmers discard some 500,000 sows every year, close to 50% of the population.


The number of pigs slaughtered worldwide in 2018 was


That’s 406,710 every day;
16,946 every hour;
282 every minute;
4.7 every second.

In the time it takes most people to say one billion, four-hundred-and-eighty-four million, four-hundred-and-ninety-two thousand, eight-hundred-and-forty-three, between 20 and 25 pigs will have been killed. It’s a chilling thought.

  • New rules, announced in July 2020, give German pig producers eight years to remove insemination stalls and fifteen years to replace farrowing crates.
  • Outbreaks of African swine fever (ASF) are surging in China following flooding in southern parts of the country. Farmers typically bury infected pigs, and the rains may have spread the disease via groundwater. 200 million or more pigs are thought to have been culled, slaughtered early or lost to the disease in China. [GUARDIAN MONTHLY FARM UPDATE, 14 Jul 2020]
  • Multi-level pig production facilities are becoming popular in China and may become the norm in other countries.
  • Chinese researchers have discovered a new type of swine flu that can infect humans and has the potential to cause a future pandemic, according to a study published in the scientific journal Proceedings of the National Academy of Sciences (PNAS). The disease, which researchers called the G4 virus, is genetically descended from the H1N1 swine flu that caused a pandemic in 2009. G4 now shows ‘all the essential hallmarks of a candidate pandemic virus,’ said the study.