Strong winds can exacerbate the spread of pathogens in outdoor chicken farms

Farmers who keep their chickens outdoors may want to keep an eye on the weather. A study of chicken farms in the West found that high winds increased the prevalence of Campylobacter in outdoor flocks, a bacterial pathogen in poultry that is the single largest cause of foodborne illness in the US

The researchers found that about 26 percent of individual chickens had the pathogen on the study’s “open-range” farms, which included organic and free-range farms. Strong winds in the week before sampling and the location of farms in more intensive agricultural areas were associated with a higher prevalence of Campylobacter.

“Farmers need to be aware of the risk,” said co-lead author Olivia Smith, a recent Ph.D. graduate of the School of Biological Sciences. “These environmental factors affect whether poultry are going to have foodborne pathogens, so farmers need to be aware of what’s around them. If it’s very windy and if they’re in really agricultural areas, that’s a problem.”

To help reduce exposure to Campylobacter, the researchers suggested farmers consider installing windbreaks and monitor the weather so they can bring the chickens inside during periods of high winds that could blow the bacteria into their farms from nearby fields and livestock areas.

For the study, published in the journal Animals, researchers examined chicken droppings taken from 27 farms in California, Oregon, Washington, and Idaho. They sampled most farms once a year for three years. They found that the majority of herds on these farms, 69.4%, had some incidence of campylobacter.

The researchers also interviewed the farmers about their management practices as well as the types, breeds and ages of their chickens. Only 11 of the farms in the study were officially certified organic, but all farmers avoided using chemicals on their flocks, including antibiotics, vaccines or drugs that kill pests.

This is almost the exact opposite of commercial poultry producers who usually raise birds indoors in closed barns and medicate them. These producers also select chicken breeds for efficiency, such as broilers that can grow fast and large providing a lot of meat, or layer breeds that can produce the most eggs with the least amount of feed.

The growing market for local, organic food production has different values, said Jeb Owen, a WSU entomologist and senior author on the paper. These farmers reduce or completely eliminate chemicals, keep a wide range of chicken breeds and allow their flocks to roam outside because they believe it is better for the animal and the environment. It’s also what many consumers want, Owen said. But it doesn’t come without risks.

“We’ve spent a century raising birds indoors, and we’ve forgotten all these parasites and pathogens that plagued chickens, but they didn’t go away,” he said. “Now you have this rapidly exploding market of producers who want to raise their birds outside but have no knowledge of the history of disease risk.”

Being outside means chickens are exposed to disease from wild birds and simply from contact with the ground, where they can pick up pathogens spread by the droppings of other infected birds.

Owen’s lab has undertaken a series of investigations to better understand the disease risk faced by free-range chicken farms, including a study on intestinal parasites such as worms that live in the digestive tracts of birds and another on ectoparasites, those that found in skin and feathers. His team is also undertaking a study to better understand the disease resistance of the many different breeds raised on these types of farms. The overall aim is to help farmers mitigate risk.

“If they are not already doing so, farmers should establish a professional relationship with a veterinarian to have their herds checked and monitored on a regular basis,” he said. “Whether it’s for productivity or animal welfare, you don’t want your animals to be sick.”