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Pigs are remarkable creatures– joyful, curious, loyal, and widely considered by animal researchers to be the most intelligent domestic animals on the planet. In tests designed to measure intelligence and problem-solving skills, pigs consistently surpass both dogs and three-year old children. (1) Some researchers believe that, like humans and other highly intelligent mammals, pigs possess a “theory of mind,” the ability to attribute mental states to others, and to understand that others have beliefs, desires, and intentions that are different from one’s own. (2) It is perhaps for this reason that pigs are often capable of acts of profound empathy.

When Jo Ann Altsman suffered a heart attack in 1998, her 200 pound companion pig, Lulu, ran out of the house, broke through the front gate and waited by the road for a car to pass. Each time she saw a car coming, Lulu lay down in the middle of the road. Soon, one man stopped, and when he got out of his car, Lulu jumped up and ran toward the house, making distress noises. The man followed and knocked, intending to tell the owner that something was wrong with her pig. Instead, he discovered Jo Ann crying for help and was able to call an ambulance. If another 15 minutes had passed, Jo Ann would not have lived.

In another incident, an undercover investigator for Mercy For Animals, working on a pig breeding farm, reported the following observation: “I saw firsthand how clever and empathic pigs can be. A sow and her entire litter had escaped their crate and gathered in the hallway. I discovered the sow had loosened steel pegs in two different places. I told a coworker this story; she said when a sow figures out how to unlock her crate, she often goes around unlocking all of the others as well….”

Pigs display a similar impulse toward collaboration in the wild. Highly social animals, pigs in nature live in small, matriarchal groups called sounders, typically composed of 2-6 sows and their young. Within the sounder, if the other sows are also nursing young, mother pigs may share caretaking duties and even nurse one another’s babies, so that sows going foraging have more time to find food. (3) Often, two sows will pair off as foraging partners and as sleepmates within the larger communal nest in which wild pigs sleep, cuddled close to each other. Siblings also form close relationships, and often maintain these bonds into adulthood. (4)

People who care for pigs on sanctuaries, or who live with pigs as companions, know they are identical to dogs in their love of giving and receiving affection. In healthy environments, pigs form deep and lifelong friendships not only with other pigs, but with individuals of other species, including dogs, rabbits, and humans. Pigs are very expressive, and greet one another enthusiastically by touching snouts and vocalizing. (5) They have an incredible sense of hearing far beyond that of humans, and can distinguish very subtle differences in tone. Pigs employ more than 20 different sounds (with additional subtypes of some sounds) to communicate during feeding, courtship, exploring, and other social activities. (6) These vocalizations enable pigs to convey to others their location, mood, well-being, and desires.

Life for Breeding Sows

Commercial Breeding and Birth

In a natural habitat, a few days before birth pregnant sows leave the group and begin to search for a safe, secluded site in which to build a nest. Sows are very particular about the nest environment and may travel for miles before finding a spot that feels sufficiently private and protected. (7) Often, they prefer dry, wooded areas sheltered by branches. Once the site has been chosen, the sow constructs a soft, comfortable nest by digging a hollow in the earth, filling it with grass, leaves and twigs, and lining it with branches.

But on factory farms, the lives of mother pigs and their piglets are a living hell. “Megafarms”—those with more than 10,000 breeding sows in one location—are the dominant production type. Smithfield Foods, the largest pig producer in the United States and in the world, keeps more than 1.2 million breeding sows, and the next six largest pig-producing operations confine more than 100,000 sows each.

Sows kept for breeding are artificially inseminated, then confined for the entire four months of their pregnancy in “gestation crates.” These 2-foot wide crates are so restrictive that sows can literally never turn around, and can barely lie down without portions of their body protruding outside the bars. (8) Sows lay and stand in these maddening conditions night and day for 16 weeks, panicked, confused, increasingly hopeless, and eventually so depressed that they often become unresponsive. Others go insane from boredom and despair, constantly biting the bars of their crates and banging their heads against the metal doors. (9)

When they are ready to give birth, mother pigs are moved to “farrowing crates” that are also typically 2 feet in width. (10) Piglets can reach their mothers to nurse, but, once again, sows are prevented from ever turning around, and must lay or stand on slatted metal flooring through which their urine and excrement fall. Inevitably these floors, on which sows nurse, sleep and stand, are covered in accumulated layers of waste, which is demoralizing for the sows; pigs are extremely fastidious animals and, when permitted, always establish separate toilet areas far from their nests. Slatted flooring also causes severe leg problems for sows and piglets.

The deeply rooted drive in sows to express natural nesting and mothering behaviors is completely thwarted in the cruel confines of a farrowing crate. Though sows spend hours lining their secluded nests with soft materials in nature, in farrowing crates they receive no bedding whatsoever. According to a Humane Society report, “Sows in intensive confinement operations attempt to perform nesting behavior—pawing the floor and nosing the bars of the crate—even in the absence of a suitable site and without nest building materials. Sows may even wear down their front hooves and suffer from abrasions on their snouts from performing this behavior in contact with the concrete floor.” (11)

Life for Young Pigs

Cruel confinement

Life for baby pigs is no better. In 2011, nearly 111 million pigs were raised and slaughtered in the United States. Most of these animals are now born and raised intensively in large indoor confinement operations. (12) Piglets are taken from their mothers when they are as young as 10 days old, and crowded together in barren rooms called “nurseries,” where they live until old enough to be transported to confined “finishing” pens. (13) Some of the largest commercial finishing operations house more than 5,000 pigs. (14) Pigs raised in these systems are unable to engage in any important natural behaviors, including rooting, wallowing, exploring, nest-building, and foraging, and are unable to form natural familial or social groups. Like their confined mothers, young pigs exhibit dejection, learned hopelessness, and neurotic coping behaviors indicative of mental disturbance. 

Their physical health also rapidly degrades in overcrowded, unnatural conditions. Confined for months on slatted floors above pits of their own excrement, pigs suffer miserable respiratory disorders as a result of constant exposure to noxious levels of ammonia. Crippling leg disorders are also pervasive due to the unnatural flooring and lack of exercise. Many pigs do not survive to six months of age, when pigs are normally killed after reaching slaughter weight of 270 pounds.


Every year in the U.S., 50 million male piglets are castrated without anesthetic in order to produce pork that doesn’t carry the stronger (and less popular) flavor of meat that comes from intact animals.(15) Workers use a scalpel or razor to cut through the flesh to the restrained animals’ testicles, then pull them out. According to a castration guidelines manual, workers are instructed to: 1) Make a cut 1 – 2 cm long in the bottom of the scrotum. The testicle should pop out through the cut. 2) Pull the testicle out of the scrotum and cut through the white cord leaving the red blood vessel uncut. 3) Pull the testicle out slightly further and twist it around several times before cutting the twisted blood vessel by scraping up and down with the knife. Piglets scream throughout this excruciating procedure. But that is just the beginning of their torment. In extremely crowded conditions, with no opportunity to explore a natural environment or express instinctive behaviors, piglets are prone to nervous stress behaviors such as biting one anothers’ tails, so farmers often chop off piglets’ tails and use pliers to break off the ends of their teeth—all without anesthetic or painkillers. (16) For identification purposes, farmers also cut notches into piglets’ ears. (17) Pigs’ ears are full of nerves and blood vessels, just like humans’ ears. These routine mutilations are painful and exceedingly traumatic for young pigs.


In commercial confinement operations, pigs are not used to new experiences and unfamiliar places, so moving them between production sites often causes them great stress. Most pigs raised for slaughter have not been treated well by humans, and often become fearful and chaotic when approached by handlers. Willful acts of abuse to pigs by workers are constantly being recorded by undercover investigators. A recent investigation by Mercy for Animals revealed the following:

  • Mother sows confined to barren metal crates barely larger than their own bodies – unable to turn around or lay down comfortably for nearly their entire lives
  • Workers ripping out the testicles of conscious piglets without the use of painkillers
  • Piglets suffering with herniated intestines, due to botched castration
  • Conscious piglets having their tails painfully sliced into and yanked off with dull clippers
  • Large, open, pus-filled wounds and pressure sores
  • Sick and injured pigs left to languish and slowly die without proper veterinary care
  • Mother pigs – physically taxed from constant birthing – suffering from distended, inflamed, bleeding, and usually fatal uterine prolapses
  • Management training workers to throw piglets across the room – comparing it to a “roller coaster ride”

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Transport and Slaughter

In the U.S., after piglets are taken from their mothers they are shipped to Corn Belt states such as Illinois and Indiana for “growing” and “finishing.” When they are transported on trucks, piglets weighing up to 100 pounds are given no more than 2.4 square feet of space, and are exposed to freezing and scorching weather extremes. Once pigs reach “market weight” they are again transported, this time to slaughter. Pigs are shipped from all over the U.S. and Canada to slaughterhouses mostly located in the Midwest. According to industry reports, more than 1 million pigs die en route to slaughter each year, many from heat stroke. (18) Pigs are particularly susceptible to heat stress because they lack functioning sweat glands. In natural settings, pigs are able to cool themselves by wallowing in mud or water, but when confined on transport trucks, they are unable to thermoregulate. The stress of rough handling and transport also contributes to elevated body temperatures, which is compounded by dehydration from the standard practice of withholding water from animals before and during transport. (19)

When pigs reach the slaughterhouse, they are herded down a ramp into a restraining chute. The pigs scream in terror as they are forced closer to the front of the line. A typical slaughterhouse kills about 1,000 hogs per hour.(20) The huge number of animals killed makes it impossible for pigs’ deaths to be humane and painless. Before their throats are slit, pigs are “stunned” by one of two methods: electrocution or the firing of a long retractable bolt into the brain with a bolt gun. Because of improper stunning, many hogs are still alive when they reach the scalding-hot water tanks that remove their hair.(21) It is not uncommon for pigs to be “walking and squealing after being stunned [with a bolt gun] as many as four times.”(22)

What About Humanely Raised Pigs?

Ultimately, no matter how well they’re treated, there’s nothing humane about harming and killing animals for pleasure– which is all that eating animals amounts to when it isn’t a necessity for survival. If you are concerned with making ethical food choices, please visit our Humane Farming Myth page for important information, as well as our Ethics of Eating page for insights into the ethics of eating animals. And if you’re purchasing meat, eggs or dairy from a “cage-free” or “free-range” label, it’s important to realize that humane labeling is often a marketing ploy that preys on consumer willingness to pay more for better treatment of animals. Our Deciphering Humane Labels and Loopholes page provides a full list of current welfare-related packaging claims, and will help you understand the various inhumane practices still permitted under terms like “cage-free” and “free-range.”

Go Cruelty-Free

Fortunately, it’s easier than ever to choose a diet based on kindness and compassion. Please visit our Vegan Food and Nutrition page for information on transitioning to a cruelty-free diet, with tons of helpful tips and delicious recipes.


(1) “New Slant on Chump Chops,” Cambridge Daily News, 29 Mar. 2002

(2) Watson L. 2004. The Whole Hog: Exploring the Extraordinary Potential of Pigs (Washington, DC: Smithsonian Books, p. 183).

(3) Graves HB. 1984. Behavior and ecology of wild and feral swine (Sus scrofa). Journal of Animal Science 58(2):482-92.

(4) Graves HB. 1984. Behavior and ecology of wild and feral swine (Sus scrofa). Journal of Animal Science 58(2):482-92.

(5) Stolba A and Wood-Gush DGM. 1989. The behaviour of pigs in a semi-natural environment. Animal Production 48(2):419-25.

(6) Signoret JP, Baldwin BA, Fraser D, and Hafez ESE. 1975. The behaviour of swine. In: Hafez ESE (ed.), The Behaviour of Domestic Animals, 3rd Edition (London, U.K.: Baillière Tindall, p. 299).

(7) Jensen P. 1986. Observations on the maternal behaviour of free-ranging domestic pigs. Applied Animal Behaviour Science 16(2):131-42.

(8) McGlone JJ, Vines B, Rudine AC, and DuBois P. 2004. The physical size of gestating sows. Journal of Animal Science 82:2421-7.

(9) Mason G and Rushen J. 2006. Stereotypic Animal Behaviour: Fundamentals and Applications to Welfare, 2nd Edition (Wallingford, U.K.: CABI, p. 347).

(10) Anil L, Anil SS, and Deen J. 2002. Evaluation of the relationship between injuries and size of gestation stalls relative to size of sows. Journal of the American Veterinary Medical Association 221(6):834-6.

(11) Humane Society of the United States, The Welfare of Breeding Sows

(12) U.S. Department of Agriculture. 2007. Swine 2006, Part I: Reference of swine health and management practices in the United States. USDA:APHIS:VS, CEAH. Fort Collins, CO, #N475.1007, p.38.

(13) Anderson AL. 1957. Swine Management, 2nd Edition (Chicago, IL: J.B. Lippincott Company, p. 110).


(15) Joellen Perry and Mary Jacoby, “These Little Pigs Get Special Care From Norwegians,”The Wall Street Journal, 6 Aug. 2007.

(16) Glenn Selk, “Managing the Sow and Litter,” Oklahoma Cooperative Extension Service, July 2003.

(17) L. Michael Neary and Ann Yager, “Methods of Livestock Identification,” Purdue University Department of Animal Sciences, Dec. 2002.

(18) John Goihl, “Transport Losses of Market Hogs Studied,” Feedstuffs, 28 Jan. 2008.

(19) Schrama JW, van der Hel W, Grossen J, Henken AM, Verstegen MWA, and Noordhuizen JPTM. 1996. Required thermal thresholds during transport of animals. The Veterinary Quarterly 18(3):90-5.

(20) Lance Gay, “Faulty Practices Result in Inhumane Slaughterhouses,” Scripps Howard News Service, Feb. 2001.

(21) Joby Warrick, “They Die Piece by Piece,” The Washington Post, 10 Apr. 2001.

(22) Warrick