Flock Behavioral Changes Could Signal Campylobacter Infection in Chickens

A study by scientists at Oxford University’s Department of Zoology has discovered that a new technique to monitor the movement of chickens may be able to predict which flocks are at risk of infection with Campylobacter.

Campylobacter is the main cause of foodborne disease in humans in Europe and North America and a major reservoir of infection is poultry meat. The pathogen has proved difficult to eliminate from the food chain and surveillance results typically show contamination rates of 70% or more in chicken carcases on retail sale.

The Oxford University researchers used cameras to monitor the behaviour of chicken flocks by analysing the ‘optical flow’ patterns of the birds inside broiler houses. This technique works by detecting temporal and spatial patterns formed by changes in brightness in moving images. Data was collected for 31 commercial broiler flocks and faecal samples were also collected to test for Campylobacter infection in the birds at different ages.

The results revealed that Campylobacter-positive flocks showed less average movement and less uniform movement than uninfected flocks as early as ten days into their lives. According to corresponding study author Professor Marian Dawkins, “Our results provide statistical evidence of a link between broiler chicken flock behaviour and Campylobacter status.”

It is not yet possible to say whether the changes in behaviour are a direct result of infection, or indicate poor health that predisposes the birds to colonisation by the bacteria later. However the findings are said to be consistent with mounting evidence that Campylobacter is harmful to the health of chickens and not a harmless inhabitant of the gut.

It is hoped that the new technique will help farm managers monitor the health of commercial chicken flocks and provide warning of potential infection much more quickly than conventional microbiological testing. Early intervention could improve both food safety and animal welfare.

The study findings are published in the journal Proceedings of the Royal Society B and can be found in full here.