Industrial chicken farms are fuelling the spread of diarrhoea-causing bacteria, study finds

Industrial poultry farming has led to a more than 100-fold increase in the spread of Campylobacter, the most common bacterial cause of gastroenteritis in the world, according to a new study by the University of Oxford.Intensive poultry farming has transformed global bird populations, concentrating billions of chickens into dense industrial systems that fundamentally reshape ecological space, researchers at Ineos Oxford Institute for Antimicrobial Research said, after analysing around 2,800 bacterial genomes from chickens and wild birds in 30 countries between 1979 and 2024.Birds are significant pathogen reservoirs and these changes can have important consequences for the spread of infectious diseases jumping from animals to humans. The number of chickens has risen sevenfold since the 1960s to roughly 31 billion birds today, the authors said, increasing the risk of environmental spillover of different diseases into the human food chain.