Intensive animal farming, industrial livestock production, and macro-farms, also known by opponents as factory farming, is a type of intensive agriculture, specifically an approach to animal husbandry designed to maximize production, while minimizing costs. To achieve this, agribusinesses keep livestock such as cattle, poultry, and fish at high stocking densities, at large scale, and using modern machinery, biotechnology, and global trade. The main products of this industry are meat, milk and eggs for human consumption. There are issues regarding whether intensive animal farming is sustainable in the social long-run given its costs in resources. Analysts also raise issues about its ethics.
There is a continuing debate over the benefits, risks and ethics of intensive animal farming. The issues include the efficiency of food production, animal welfare, health risks and the environmental impact (e.g. agricultural pollution and climate change).
Intensive animal farming is a relatively recent development in the history of agriculture, utilizing scientific discoveries and technological advances to enable changes in agricultural methods that increase production. Innovations from the late 19th century generally parallel developments in mass production in other industries in the latter part of the Industrial Revolution. The discovery of vitamins and their role in animal nutrition, in the first two decades of the 20th century, led to vitamin supplements, which allowed chickens to be raised indoors. The discovery of antibiotics and vaccines facilitated raising livestock in larger numbers by reducing disease. Chemicals developed for use in World War II gave rise to synthetic pesticides. Developments in shipping networks and technology have made long-distance distribution of agricultural produce feasible.
Agricultural production across the world doubled four times between 1820 and 1975 (1820 to 1920; 1920 to 1950; 1950 to 1965; and 1965 to 1975) to feed a global population of one billion human beings in 1800 and 6.5 billion in 2002.