Sources and Methodology

Sources for specific company profiles and practices are cited directly within the relevant Wickedpedia, Hall of Shame and Labels Lie pages. This page focuses on the headline statistics and top-level claims that appear across our campaign and About pages.

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The Scale of Factory Farming

Over 90% of farmed animals globally are living in factory farms at present.

Combine land animals and fish, and the final estimate comes to 94% of livestock living on factory farms.

99% of US farmed animals live on factory farms, study shows

85% of farmed animals are confined in factory farms here in the UK.

Annual slaughter figures are drawn from DEFRA’s Agriculture in the United Kingdom 2024 report (Chapter 8: Livestock) and the Food Standards Agency’s 2024 Slaughter Sector Survey in England and Wales. The breakdown includes over one billion chickens, 15 million turkeys, more than 10 million pigs, around 15 million sheep and lambs, and approximately 2.8 million cattle.

The Growth of Factory Farming in the UK

The industrialisation of UK farming accelerated decisively after the 1947 Agriculture Act, which committed the government to maximising food production and introduced financial incentives that drove the adoption of intensive methods, larger machinery, and the consolidation of smaller holdings into larger units.

The number of farms in the UK declined by 35% between 1949 and 1999, with farms increasing in size as smaller holdings were absorbed. In 1949 only 1% of farms covered 500 acres or more; by 1999 that had risen to over 6%.

An investigation by the Bureau of Investigative Journalism found that the number of intensive pig and poultry farms in the UK increased by 26% between 2011 and 2017, with almost 800 US-style megafarms now operating across the country, the largest holding more than a million chickens, 20,000 pigs, or 2,000 dairy cows.

Long-term DEFRA historical statistics on UK farm numbers, livestock numbers, and agricultural output since the 1940s.

Research by Portsmouth University and City, University of London, published by Sustain in 2022, found that farmers supplying UK supermarkets with common food products are typically left with less than 1% of the profit, with processors receiving up to ten times the farmer’s return for the same product. The report, Unpicking Food Prices, found this pattern across beef, dairy, bread and fresh produce, and attributed it to the concentration of power in the hands of large processors and retailers.

The Rise of Factory Farming

Pre-1990 figures are estimates reconstructed from proxy data, including farm consolidation rates, poultry industry records, and meat production share. No direct survey data exists for these periods.

The UK’s lower headline figure (~73%) compared to the US (~99%) is partly a definitional artefact. The UK regulatory definition (requiring a pollution permit) applies only to very large operations, meaning many smaller intensive farms go uncounted. The broader estimate (~85%) uses a lower threshold and includes fish farming.

Global figures include significant uncertainty, particularly for farmed fish, where data is typically reported in tonnes rather than animal numbers.

All figures refer to the percentage of animals in factory farm conditions at any given time, not the percentage slaughtered annually.

US 2022: ~99%. Sentience Institute — US Factory Farming Estimates (2024).

Global 2020s: ~90%. Sentience Institute — Global Farmed & Factory Farmed Animals Estimates.

Global 1990: ~30% of meat. Wikipedia — Intensive animal farming (citing Worldwatch Institute).

UK 2020s: ~73%. CIWF Factory Farm Map.

UK 2020s: ~85%. World Animal Protection / Plant Based News (broader definition including fish).

UK +26% in 6 yrs. UK Parliament Written Evidence on Scale of Intensive Indoor Livestock Farming (2021).

UK +13% in 5 yrs / +209 farms. World Animal Protection — Confined in Cruelty Report (2024).

Historical proxy data. DEFRA Agriculture in the UK; UK Parliament Historical Agricultural Statistics (SN03339); Wikipedia — Intensive animal farming (farm consolidation figures)

EU: Friends of the Earth Europe/Eurostat (EU, 2024).

End Factory Farming by 2040

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Public Attitudes to Factory Farming

56% of UK respondents support a ban on factory farming, with only 22% opposed, consistent across demographic and political groups. The research also found that greater knowledge of factory farming practices is directly associated with stronger opposition.

Knowledge and attitudes to factory farming practices in the UK and US: Can minds and behaviour be changed? Social Change Lab for Project Slingshot, 2025.

CO2 Gas Chambers

In 2024 the Food Standards Agency Slaughter Sector Survey identified that of pigs reared in England and Wales 90% are stunned by being exposed to high concentration CO2 using paternoster CAS systems.

Currently, 90% of pigs in the UK are killed using high-concentration CO2

The AWC concluded that to prevent pigs from experiencing avoidable pain, distress or suffering at slaughter associated with high concentration CO2, its use should be prohibited and that the transition period provided should be as short as possible.

Hidden camera at slaughterhouse appears to show ‘utterly inhumane’ use of CO2 to stun pigs before slaughter

Around 95% of chickens raised for meat in the UK are fast-growing breeds.

Slower-growing breeds currently account for approximately 5% of the UK broiler market, according to Farmers Weekly, citing industry figures. This is consistent with data from Compassion in World Farming, which puts slower-growing production at around 11% of UK output. Fast-growing breeds are selectively bred to reach slaughter weight in five to six weeks, compared to the 70 to 81 days required for slower-growing and organic birds.

Around 40 to 45 million male chicks are killed in the UK each year, primarily by gassing, within hours of hatching.

This figure is drawn from the UK Government’s Animal Welfare Committee (AWC) opinion on alternatives to culling newly hatched chicks, published in 2023 and cited in the government’s own Animal Welfare Strategy for England. The AWC recommended that routine culling should be made illegal as soon as reliable in-ovo sexing technology is commercially available in British hatcheries. The practice occurs across all commercial egg production systems, including free-range and organic, and takes place predominantly in two major hatcheries in England.

Animal Welfare Committee (2023). Opinion on alternatives to culling newly hatched chicks in the egg and poultry industries.

UK Government Animal Welfare Strategy for England (2025), citing AWC 2023.

Antibiotic Resistance

The link between farm antibiotic use and the development of resistance in human infections is confirmed by the World Health Organisation, which explicitly states that overuse of antibiotics in animals contributes to the emergence of antibiotic resistance, and recommends that the farming industry stop routine and preventative use of antibiotics in healthy animals.

In the UK, scientists estimate that 7,600 deaths a year are directly attributable to antibiotic resistance, with a further 35,200 deaths associated with it. A 2024 report by World Animal Protection, based on research by the University of Bologna, calculated that antibiotic-resistant bacteria specifically linked to factory farm antibiotic use — including resistant strains of E. coli and Salmonella — caused nearly 2,000 human deaths in the UK in 2022 alone, a figure projected to rise to 2,400 by 2050.

Environmental Impact

Food systems are responsible for approximately 25-30% of global greenhouse gas emissions, rising to around one-third when all agricultural products are included. Animal-based foods account for 57% of food production emissions, compared to 29% for plant-based foods.

The global food system’s greenhouse gas footprint, broken down by source including livestock, land use change, and supply chains.

Livestock supply chains account for approximately 14.5% of all global anthropogenic greenhouse gas emissions, with cattle alone responsible for around two-thirds of that total.

Agriculture drives at least 75% of global deforestation, with livestock grazing responsible for close to 40% of forest loss globally. More than three-quarters of all soy produced worldwide is fed to livestock, not consumed directly by humans.

The world loses around 5 million hectares of forest every year, 95% of it in the tropics, with agricultural expansion the dominant cause.

Only 14% of English rivers currently meet good ecological status. Agriculture affects more than 60% of the rivers that are failing that standard, with animal waste, fertiliser runoff, and pesticides among the leading causes.

Parliamentary Office of Science and Technology briefing on agricultural pressures on freshwater ecosystems, confirming agriculture and sewage effluent as the leading causes of English rivers failing to meet good ecological status.

WWF’s 2022 Future of Feed report found that despite dairy and meat products providing only 32% of calories consumed in the UK, livestock and the land used to grow their feed account for 85% of the country’s total agricultural land use. More specifically, wheat and barley grown to feed farmed animals occupies 40% of the UK’s entire arable land area, with half of the UK’s annual wheat harvest going to livestock rather than human consumption.

FAO research on global livestock feed conversion ratios found that, when considering only human-edible feed inputs, pigs and poultry require between 6 and 16kg of plant protein per kg of animal protein produced, while ruminants require around 6kg. These figures vary significantly by species, production system, and whether total feed or only human-edible feed is counted. The core point — that cycling plant protein through animals to produce animal protein involves a significant net loss of food — is consistent across the literature.
Mottet, A. et al. (2017). Livestock: On our plates or eating at our table? A new analysis of the feed/food debate. Global Food Security 14, 1–8.

Reducing reliance on industrial animal agriculture could feed a growing global population using dramatically less land, water, and resources.

The most comprehensive analysis of food’s environmental impacts to date — Poore and Nemecek’s 2018 study in Science, based on data from 38,700 farms across 119 countries — found that without meat and dairy, global farmland use could be reduced by more than 75% while still meeting global food needs. The study concluded that even the lowest-impact animal products typically have greater environmental costs than plant-based alternatives.

The EAT-Lancet Commission, co-chaired by Professor Walter Willett of Harvard T.H. Chan School of Public Health and published in The Lancet in 2019, demonstrated that feeding 10 billion people a healthy diet within planetary boundaries by 2050 is achievable, and that a shift toward plant-rich diets could prevent 11 million deaths annually while avoiding severe environmental degradation. An updated Commission report in 2025 strengthened these findings, estimating that transforming food systems could cut agricultural greenhouse gas emissions by more than half and prevent up to 15 million premature deaths per year.

The FAO’s landmark 2006 report, Livestock’s Long Shadow, documented that the livestock sector occupies 70% of all agricultural land globally, is responsible for 65% of human-related nitrous oxide emissions, 37% of methane, and 64% of ammonia, and identified it as a leading driver of land degradation, water use and depletion, and biodiversity loss.

Poore, J. & Nemecek, T. (2018). Reducing food’s environmental impacts through producers and consumers. Science, 360(6392), 987–992.

Willett, W. et al. (2019). Food in the Anthropocene: the EAT-Lancet Commission on healthy diets from sustainable food systems. The Lancet, 393, 447–492.

Steinfeld, H. et al. (2006). Livestock’s Long Shadow: Environmental Issues and Options. FAO, Rome.

Market Concentration

Sustain’s 2024 “Stink or Swim” report found that five large corporate conglomerates, including Cargill and JBS, act as holding companies for the majority of UK intensive livestock processors, and that all major UK retailers are linked to at least one of the agribusinesses assessed.

Sustain’s analysis also found that Moy Park controls approximately 30% of the UK poultry market and Avara Foods controls over 20%, collectively accounting for more than half of UK chicken production.

Corporate Conduct

Detailed sources for all claims made about named companies are cited directly within each individual Hall of Shame profile. Information draws on publicly available sources including Companies House filings, annual reports, court records, regulatory decisions, and published investigative journalism. All claims about named companies have been subject to legal review prior to publication. Where a company has disputed a claim or provided a response, this is noted within the relevant profile.

End Factory Farming by 2040

It's time to bring it all down. Tell the government to block new factory farms and ban factory farming by 2040.
Sign the petition