New research from the UK’s University of Oxford has revealed that monitoring the movement of chickens can show the early warning signs of flocks that at risk of becoming infected with Campylobacter. This is one of the most common bacterial pathogens causing food poisoning in humans, and cases are linked to the consumption of raw or undercooked chicken.

Scientists at the university used a camera system to analyze the “optical flow” of chickens in the poultry house. They found that at-risk flocks could be detected when the birds are just 7 to 10 days of age, which is much sooner than with conventional sampling methods on the farm.

In spite of efforts to improve biosecurity on farms and in slaughterhouses, Campylobacter is proving difficult to eliminate from the food chain. This new early warning system, however, offers the potential to transform Campylobacter control to the benefit of producers, consumers and the birds themselves.

“Humans consume nearly 60 billion chickens a year – more than any other animal,” said Dr. Frances Colles from the University's Department of Zoology and lead author of the study. “At the same time, there is a worldwide epidemic of human gastroenteric disease caused by Campylobacter. It is estimated that up to four-fifths of this disease originates from contaminated chicken meat.

“Despite intensive efforts to improve on-farm biosecurity practice over the past decade, more than 70 percent of EU broiler chicken flocks remained Campylobacter-positive at slaughter during 2008, and the incidence of human disease continues unabated. This suggests that environmental contamination of growing broilers may not be the only cause of high rates of Campylobacter infection in chickens and that key points for intervention – for example, in breeder flocks, hatcheries or management in the first week of chick life – remain unrecognized.”

“We used a novel and non-invasive way of monitoring the behavior of chickens throughout their lives that involved analyzing the optical flow patterns from cameras inside broiler houses,” explained Professor Marian Dawkins, Professor of Animal Behavior at Oxford and corresponding author on the paper. “Optical flow works by detecting the patterns formed by changes in brightness in moving images, both temporally and spatially. It is computationally simple and does not require tagging or marking individual animals, making it ideal for long-term continuous monitoring of large groups of similar animals such as egg-laying hens and broiler chickens, where optical flow is predictive of key welfare measures such as mortality rate.”


For 31 commercial broiler flocks, the researchers carried out optical flow analyses, and collected and tested fecal samples for Campylobacter at different ages using standard lab methods.

Campylobacter-positive flocks showed less average movement and less uniform movement than flocks without the bacteria – as early as 10 days of age – and it was not impacted by external temperature.

“Our results provide statistical evidence of a link between broiler chicken flock behavior and Campylobacter status,” concluded Dawkins. “It is not certain whether the changes in optical flow are a direct effect of Campylobacteror whether a general reduction in the birds' overall health predisposes them to Campylobacter colonization at a later date. However, the findings are compatible with the growing evidence that Campylobacter may be detrimental to chickens' health, rather than simply being harmless gut bacteria.

“Use of this optical flow information has the potential to make a major impact on the management of commercial chicken flocks, for the benefit of producers, consumers and the birds themselves. Farm managers able to access such information in real time would have early warning of which of their flocks were most at risk of health and welfare problems, enabling them to intervene before these became serious and helping them to produce higher quality, healthier food with better welfare,” she added.

The paper, “Monitoring chicken flock behaviour provides early warning of infection by human pathogen Campylobacter” is published in Proceedings of the Royal Society B.