How Are Pigs Killed: The Brutality Of Animal Agriculture

How Are Pigs Killed (Slaughtering Methods) - Almost Zero Waste

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How are pigs killed before reaching the stores and perhaps your table? 

A rather uncomfortable question, however, a logical one. 

The truth is that behind the walls of pig factories, there is a lot of pain, suffering, and horror. 

In this article, you will learn about how pigs are raised, how they are slaughtered, and other related questions, including:

  1. How are pigs killed?
  2. Slaughtering methods in-depth
  3. Pig farming: effects on the environment
  4. Pig intelligence ranking 
  5. FAQ:
    – Why are pigs boiled alive?
    – Do pigs cry when slaughtered?
    – Do pigs suffer when slaughtered
    – How long do pigs live before slaughter?
    – What does the word “humane” mean?
    – Can we humanely kill a pig? 
  6. Conclusion

How Are Pigs Killed (Slaughtering Methods) - Almost Zero Waste

How are pigs killed?

There are two main phases when slaughtering pigs: 1) handling and moving of pigs and 2) killing methods.

The most common slaughtering methods are – electrical stunning, gas stunning, stunning using a captive bolt pistol to shoot the animals directly into the brain. (source)

These methods often include aggressive restraining of the pigs, which is very stressful and fearful for the animals. 

Some stunning methods cause unconsciousness and death; others only cause unconsciousness.

That’s why they are always followed by a killing method such as bleeding (an animal’s throat is slit) or pithing. (source)

The bleeding of ineffectively stunned animals and those recovering consciousness leads to horrific pain and fear.

The most common killing methods in the different parts of the world are:

  • Europe: Electrical stunning (head-only and head-body) and gas stunning (carbon dioxide gas and inert gas mixtures)  
  • Australia: group gassing where pigs are transferred into a gas chamber and gassed to death
  • The US: captive bolt pistol/gunshot, electrical or gas stunning
  • The UK: gas and electrical stunning
How Are Pigs Killed (Slaughtering Methods) - Almost Zero Waste

Slaughtering methods in-depth:

Electrical stunning:

A method that causes epileptic seizures and instant unconsciousness. There are two main permitted methods:

1) Head-only stunning (reversible outcome) – involves two electrodes placed on either side of the head. The animal will regain consciousness within 30 seconds after being stunned. (source, page 74

2) Head-to-body (irreversible cardiac arrest outcome) – can cause different complications and adversely affect the end product.

Therefore, this method is rarely used in the industry. If used, there are many factors to consider to determine a pig’s sensitivity (weight, skin thickness, the wetness of the skin, hair length, age, etc.).

If the method is not performed correctly, it will not appear, and it will cause pain to the animal without killing it instantly.  (source, page 77

Gas stunning:

This is one of the most common methods – stunning the pigs with carbon dioxide gas.

Depending on factors like gas concentrations and exposure time, this method may be either reversible or irreversible. Studies proved that the pigs don’t go unconscious immediately.

A state of unconsciousness begins from 30 to 39 seconds after starting the procedure with 86% carbon dioxide concentration.

From 6 different studies, it was calculated that the average time to onset of unconsciousness during exposure to 80% carbon dioxide ranges average between 19 – 28 seconds.

Exposure to the gas stimulates acute respiratory distress, hyperventilation, and a sensation of suffocation.

Plenty of scientific research demonstrates that carbon dioxide stunning does not guarantee an absence of avoidable pain, suffering, and distress in pigs.

It is not immediate, and pigs suffer from fear, pain, and stress.

How Are Pigs Killed (Slaughtering Methods) - Almost Zero Waste

Penetrating captive bolt:

A gun fires a metal bolt into the animal’s brain, causing the animal to lose consciousness. (source

It is hard to stun pigs with captive-bolt equipment because: 

That means the pig won’t die immediately, and a second shot is required. 

Pig farming: effects on the environment

The industry is incredibly inhumane, but there are also various direct environmental impacts of pig production. The main ones are related to the produced manure.

High levels of manure release different nutrients into the environment. This can contribute positively by increasing soil fertility if used correctly.

However, an overload of nutrients and other substances can lead to soil and water degradation. (source)

How Are Pigs Killed (Slaughtering Methods) - Almost Zero Waste

Feces and waste is often spread to surrounding neighborhoods. This contributes to air and water pollution, potential carriers of different diseases, pathogens, bacterias, and heavy metals that can be toxic when ingested. 

People living in nearby towns have a higher risk of suffering various adverse health effects, including respiratory diseases, infections, increased risk of cancer, and other health risks. 

Intensive farming operations make pig farming the third-highest environmental impact among meats.

Overall emissions from pork production are 12.1 kg CO2-eq per kilogram of meat. To put this in perspective, the numbers for plant-based foods are: 

  • Tofu – 2.2 kg CO2e
  • Rice – 2.7 kg CO2e
  • Potatoes – 2.9 kg CO2e
  • Beans – 2 kg CO2e
  • Lentils – 0.9 kg CO2e
Source: Environmental working group

Livestock production contributes to global warming through emissions of methane and nitrous oxide.

Animal agriculture (including the production of feed crops, fertilizer manufacturing, and the shipment of meat, eggs, and milk) is responsible for 14-18% of all GHG emissions (1, 2, 3), which is more than all the transportation sector produces (cars, ships, planes, trains).  

To find more about the harmful effects of animal agriculture, read my article with 8 environmental benefits of reducing meat consumption.

How are pigs killed,can we humanely kill a pig
Source: Environmental Working Group Meat Eaters Guide: Methodology 2011, page 23

Pig intelligence ranking 

Pigs are believed to be one of the most intelligent animals.

Pigs, in particular, have sophisticated cognitive, emotional, and social characteristics and personalities.

They share many traits with animals that we consider intelligent, such as dogs.

Studies have shown that pigs are highly social animals.

They display complex cognitive abilities such as time perception, perspective-taking, self-awareness, emotion, personality, learning and memory, anticipating positive and negative situations, and more.


Why are pigs boiled alive?

Pigs are beaten, left to stand, and sleep in their feces and urine, and as all of this is not enough, there are many cases in which pigs are being boiled alive.

That type of violation continues to occur, as there is not enough supervision and fines.

Additionally, it can happen because many animals are not stunned according to procedures, mainly due to time constraints. (sources at the end)

Pigs Boiled Alive SlaughterHouse

Do pigs cry when slaughtered?

Pigs are sensitive animals, and when they are sad or upset, they cry and produce real tears. When slaughtered, pigs feel distressed; they squeal and cry in pain.

Do pigs suffer when slaughtered?

Much research exists showing pigs are highly intelligent animals that feel pain similar to humans.

They are sentient beings, which means that they can suffer and feel pain. 

Research shows that pigs squeal and vocalize when they sense pain. 

How long do pigs live before slaughter?

Factory farm pigs are sent for slaughter after just six months of their life. The average life span of pigs is 10-15 years when they live their natural life.

What does the word “humane” mean?

The term “humane” is commonly confused to mean ‘without pain, distress, or suffering.’ (even if that was the meaning, none of the killing methods could be considered as such anyway.)

The Oxford English Dictionary defines the word humane as ‘having or showing compassion or benevolence.’ 

How Are Pigs Killed (Slaughtering Methods) - Almost Zero Waste

Can we humanely kill a pig? 

Going by the true definition of the word humane, none of the slaughtering methods can be considered humane, as they cause stress and suffering to the pigs.

Putting the term ‘humane’ (showing compassion) together with ‘slaughter’ is simply an oxymoron. 

Additionally, humans can live without eating pigs. So, killing an animal that doesn’t want (and need) to die, just for our sensory pleasure (taste), cannot be humane.


Pigs are sentient, smart animals that we treat horribly, just to satisfy our sensory pleasures.  

The truth is that:

  • We do not need animal flesh and products to be healthy and to thrive. 
  • There are new unique products that can satisfy our taste buds without killing an animal.
  • The most sustainable diet is the plant-based one.

More and more people are becoming aware that killing animals is unnecessary; they are open and brave enough to change their old habits. 

If you are interested in reducing your meat consumption, you can follow my step-by-step beginner’s guide on how to transition to a 100% plant-based diet.

Do you have any questions or comments? Feel free to start a friendly conversation in the comment section below.


Pigs slaughtering:

Pig slaughter (Wikipedia)

Panel on Animal Health and Welfare (2020). Welfare of pigs at slaughter. DOI:


Panel on Animal Health and Welfare (2020). Welfare of pigs during killing for purposes other than slaughter. DOI:


Slaughtering methods:


Mia Scott (2018). The humane slaughter of pigs in the EU. DOI: https://www.researchgate.net/publication/328710482_The_humane_slaughter_of_pigs_in_the_EU



Aussie Pigs: https://www.aussiepigs.com/documents/Pig%20slaughter%20video%20Broom.pdf

Aussie Pig Farmers: https://aussiepigfarmers.com.au/pork/our-processing/abbatoir/

The US: 

National Agriculture Library. Humane Methods of Slaughter Act: https://www.nal.usda.gov/awic/humane-methods-slaughter-act

(2020). Animals and animal products. Chapter iii - Food safety and inspection service, Department of agriculture: https://www.animallaw.info/administrative/us-slaughter-humane-slaughter-livestock-regulations 

The UK:

Animal Welfare Team (2019). Results of the 2018 FSA Survey into Slaughter Methods in England and Wales. DOI: https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/778588/slaughter-method-survey-2018.pdf

Captive bolt (Slaughter Factfile): https://www.rspca.org.uk/adviceandwelfare/farm/slaughter/factfile

Meat processing: By-products: https://www.britannica.com/technology/meat-processing/By-products 

Humane Slaughter Association - Pigs: https://www.hsa.org.uk/positioning/pigs#:~:text=The%20site%20for%20stunning%20pigs,the%20forehead%20(Figure%2018)The lifespan of pigs:

Pig Transport and Slaughter: https://www.peta.org/issues/animals-used-for-food/factory-farming/pigs/pig-transport-slaughter/#:~:text=When%20allowed%20to%20live%20out,just%20six%20months%20of%20life.

Oxford Dictionary: https://www.lexico.com/definition/humane

Effects on the environment: 

Animal protection and health - Pigs and environment: http://www.fao.org/ag/againfo/themes/en/pigs/Environment.html#:~:text=The%20main%20direct%20environmental%20impact,related%20to%20the%20manure%20produced.&text=High%2Ddensity%20pig%20production%20can,eventually%20accumulate%20in%20the%20soil. 

Environmental impact of pig farming (Wikipedia): https://en.wikipedia.org/wiki/Environmental_impact_of_pig_farming 

Steve Wing (2013). Air Pollution from Industrial Swine Operations and Blood Pressure of Neighboring Residents. DOI: https://ehp.niehs.nih.gov/doi/10.1289/ehp.1205109 

Environmental Working Group Meat Eaters Guide: Methodology 2011: https://static.ewg.org/reports/2011/meateaters/pdf/methodology_ewg_meat_eaters_guide_to_health_and_climate_2011.pdf 

Heather Browning (2020). Is Humane Slaughter Possible? DOI: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7278393/#:~:text=The%20RSPCA%20(Royal%20Society%20for,humane%20slaughter%20describe%20it%20as 

Giampiero Grossi (2018). Livestock and climate change: impact of livestock on climate and mitigation strategies. DOI: https://academic.oup.com/af/article/9/1/69/5173494  

An HSUS Fact Sheet Greenhouse Gas Emissions from Animal Agriculture: https://www.humanesociety.org/sites/default/files/archive/assets/pdfs/farm/hsus-fact-sheet-greenhouse-gas-emissions-from-animal-agriculture.pdf 

Elena Lara de la Casa (2017). Intensive pig farming: Ethical considerations. DOI: https://www.researchgate.net/publication/322837792_Intensive_pig_farming_Ethical_considerations 

Pigs being boiled alive:






  1. Poor pigs.
    Me commenting will probably not change a thing. However, To not speak out is not good.
    How dare some humans think other species are to be treated like garbage and with unbearable cruelty .
    The helplessness of those pigs being boiled alive or not being properly slaughtered is a bad mark against humanity.
    As mentioned in the article, more inspectors are needed. Or better still no more slaughtering of sentient animals.
    I am going to do my best to withdraw from eating meat.

      1. you forgot to mention that you earn 10-15% of any conversion (sale) made at the url you provided; i just wanted to make that clear, since some people would take your reply as solely coming from a place of good will 🙂

        1. The link that I shared is to another article I wrote, where I don’t sell anything. So by clicking on this link, I won’t earn anything. Also, I write a disclosure at the beginning of each article – “This post and the photos within it may contain affiliate links. If you purchase something through the link, I may receive a commission at no extra charge to you.”

  2. I was a vegetarian since december 2021. My thoughts have expanded, and I don’t eat any animal parts cause I love animals sooo much. I hate supporting the fact that animals are killed so brutally while we greedily chomp on their dead flesh. This article made me love them more. I am 11 years old and my parents have tried stopping me by saying that people let the animals die and then sell them as meat. I never fell for it. Being vegetarian is super easy, pls be one for the sake of our environment. It hurts for the pigs and their mothers, such a huge agony. Nobody will like it if their family was killed so brutally

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