New undercover footage showing British pigs being gassed prior to slaughter has led to renewed calls to investigate the use of CO2.
Campaigners say the pictures – the first of their kind to be obtained in a UK abattoir – show the “utterly inhumane” nature of using CO2 to stun pigs before being killed. But the pork industry says its use is recognised as the most welfare-friendly method available, and says alternatives are being sought.
The images published today were obtained, say campaigners, using hidden cameras at Pilgrim’s Pride abattoir in Ashton-under-Lyne in north-west England in February 2021. They show pigs in groups of five or six being mechanically herded into a cage and then lowered into a Butina gas chamber in a ferris wheel-like system.
The pigs appear to be in distress as the gas concentration increases, with one still kicking after more than three minutes.
“The pigs in the video react to the first inhalation of carbon dioxide with fear and obvious discomfort,” said Donald Broom, an animal welfare professor at the University of Cambridge. “They try to escape but cannot. The gasping can be seen in all pigs where the mouth is visible. Gasping indicates poor welfare. The period of poor welfare continues until the pig loses consciousness.”
Paul Roger, a vet and founder member of the Animal Welfare Science, Ethics and Law Veterinary Association, said some pigs appeared to start waking from the gas prior to slaughter. “If this is the way animals are treated in this plant, they’re not being handled humanely. It’s an unacceptable way to treat any animal, and that really concerns me.”
Animal activist Joey Carbstrong, who captured the footage for the film Pignorant, said that the continued use of CO2 arises from the favouring of corporate profit over the interests of the animals. “We urgently need to stop using animals as resources because this kind of horror show is the result.”
Pilgrim’s UK, formerly known as Tulip, is a division of Pilgrim’s Pride Corporation, which is owned by JBS, the Brazilian-owned meat producer. Its animal welfare policy states: “At Pilgrim’s UK it is essential that all pigs are treated humanely throughout their lives and that the pig’s welfare is always at the forefront of everything we do.” It confirms that all Pilgrim’s pigs are stunned using CO2.
A Pilgrim’s Pride spokesperson said: “There is nothing to identify that this is our site, and it would be inappropriate for us to comment on that basis. Furthermore, the Food Standards Agency is legally required to be present at all sites and would routinely review any footage taken from an abattoir to ensure animals are treated humanely, and we have had no issues raised in the timeframe you have provided.”
In 2003, a government advisory body, the Farm Animal Welfare Council, said that CO2 stunning/killing “is not acceptable and we wish to see it phased out in five years”. However, its use has instead increased to 88% of all pigs in 2022.
A new scientific opinion by the European Food Safety Authority published in June 2020 stated: “Exposure to CO2 at high concentrations is considered a serious welfare concern by the panel because it is highly aversive and causes pain, fear and respiratory distress.”
Defra recently funded research into low atmospheric pressure stunning (Laps) as a potential alternative. The results showed it does not offer a humane alternative, and a 2021 Defra report into the welfare of animals at slaughter stated: “There has been no willingness on the part of abattoirs to explore inert gas mixture stunning commercially because of extended dwell time and therefore reduced throughput.”
Lizzie Wilson, CEO of the National Pig Association (NPA), said: “While we acknowledge gas stunning isn’t perfect, it is the best, most humane and efficacious commercially available option, and often the most reliable slaughter method for ensuring consistency.
“In addition, CO2 gas stunning of pigs does provide some welfare benefits; there is reduced risk of potential human error, animals remain in groups, and modern gas systems enable improved handling of pigs through use of automatic gates, which reduces the need for staff intervention and stress.”
The NPA said it organised a summit last year along with the National Farmers’ Union and British Meat Processors Association to discuss alternative gas mixtures, but concluded that there was no other viable system available. Dr Alice Brough said: “Non-aversive gases like argon or helium do offer potential alternatives, but they’re more expensive, and there’s no financial incentive for the meat industry to change their systems.”
Veterinary manager Prof Jill Thompson said: “Every effort should be made to progress towards using less aversive gasses that do not generate such reactions. This would involve changes to infrastructure in slaughter plants and would be more costly, but I believe that society would support a slight increase in the cost of products if it enabled a more peaceful stunning process for pigs.”
Peter Stevenson, head of policy at Compassion in World Farming, said: “I call on the government to ban the use of high levels of CO2 from 2026, thereby forcing the industry to belatedly invest in developing a slaughter method that is genuinely humane.”
A government spokesperson said: “The government is committed to the highest standards of animal welfare, including when animals are slaughtered or killed. We recognise there are concerns over the use of high-concentration carbon-dioxide to stun pigs, and will continue to look for viable alternatives based on the latest evidence on this issue.”