Three quarters of farm animals live on factory farms
Around three quarters of all the farmed land animals in the world, 74%, live on factory farms. That is roughly 23 billion chickens, pigs, cattle and other animals at any given moment1. Count farmed fish as well, and the share rises to 94%1.
No government or UN body counts factory-farmed animals, partly because countries do not agree on what a factory farm is. The estimate comes from the Sentience Institute, an animal-advocacy research group2, and it has been reviewed and explained by the research site Our World in Data1. It is one estimate rather than a yearly series, so the number on this page does not move.
What counts as a factory farm
The estimate uses the official US definition of a large “concentrated animal feeding operation”, known as a CAFO: a farm where animals are confined for at least 45 days a year, with no grass or other vegetation, and where the number of animals is above a certain size for each species1. In everyday terms, it means large numbers of animals kept indoors or in bare pens, at high density, and usually of breeds selected to grow as fast as possible.
That definition sets the line at a particular farm size, so the global figure depends on how it is applied to countries with very different kinds of farms. The exact number is uncertain, and the true share could be somewhat higher or lower.
In the United States, almost every farm animal
In the United States, the share is close to total. The Sentience Institute estimates that 99% of US farm animals, more than 10 billion, live on factory farms. That includes more than 99% of the chickens and turkeys raised for meat, more than 98% of egg-laying hens, more than 98% of pigs, and 75% of cattle1.
That's the share of farm animals in the United States that live on factory farms, according to the Sentience Institute
Cattle are the exception because many spend part of their lives on pasture before they are moved to feedlots. For chickens, pigs and laying hens, farming without a factory has become rare.
The costs of farming at factory scale
Factory farming spread largely because it is cheap. Keeping many animals indoors, in fast-growing breeds, produces meat, milk and eggs at the lowest cost per kilogram. The costs show up elsewhere.
The first is animal welfare. The European Food Safety Authority found that the genetics of modern meat chickens, bred for rapid growth, cause more welfare problems than any other factor on the farm7, and the chicken page explains what that means for the birds. Pregnant pigs are often kept in stalls too narrow to turn around in, as the page on pigs slaughtered for meat describes.
The second is disease. When thousands of genetically similar animals live packed together, infections spread quickly, which is one reason farms rely so heavily on antibiotics, as shown on the page for antibiotics used on farm animals. It also gives viruses like bird flu and African swine fever a lot of chances to spread.
The most factory-farmed animal of all, counted at slaughter.
Chickens slaughtered for meat
Globally, this year
Where factory farming is heading
Europe has started to set limits. The European Union banned conventional battery cages for laying hens in 2012, and more than half of the EU’s hens now live in cage-free systems such as barns and free-range farms3. Since 2013, EU farms have not been allowed to keep pregnant sows in individual stalls beyond the first four weeks of pregnancy4. In 2021, after more than 1.4 million Europeans signed the End the Cage Age initiative, the European Commission promised a law to phase out cages for farm animals by the end of 20235, but that proposal has still not appeared6.
Elsewhere, the direction is probably the opposite. Most of the growth in meat production is in Asia, Latin America and Africa, and as farms in those regions grow larger, many are adopting the same intensive methods that dominate in the United States. If that continues, the global share of factory-farmed animals is likely to rise even as parts of Europe move away from cages. That is a reasoned guess rather than a measured trend, because no one tracks the global share over time.
Pigs, one of the animals most often kept on factory farms.
More on the numbers of animals involved is on the pages for every land animal slaughtered for meat and farmed fish. The rest of what the world raises and eats is in the food section.
