In 2012, a court case in Ontario exposed a critical blind spot in Canada’s approach to managing disease risk in poultry production. A breeder operation was slated for construction just 800 metres from a farm housing great grandparent (GGP) stock under contract with Hybrid Turkeys. 

The GGP producer raised concerns, citing the farm’s uphill location and prevailing winds. He even offered alternative land five kilometres away, but the neighbouring farm refused to relocate. Jean-Pierre Vaillancourt, professor at the University of Montreal, testified in the case. “I predicted that they would have high-path AI there in a few years,” he says. That’s exactly what happened. The breeder farm was the first to report infection, followed by the nearby GGP facility.

Over a decade later, with outbreaks increasingly frequent and complex, Canada still has no regulations governing how close poultry barns can be built. Scientists warn that while most avian influenza cases originate from wild birds, barn proximity could heighten the risk of secondary spread, turning isolated outbreaks into wider regional crises.

Does barn proximity matter?

Around the world, scientists have debated how physical distance between poultry farms contributes to disease prevention, particularly in the context of highly pathogenic avian influenza (HPAI). While most Canadian outbreaks have been traced to introductions from wild birds, experts agree that under certain conditions, the virus can move between farms. The question is how often, and by what means.

According to Vaillancourt, approximately 85 per cent of avian influenza cases in Canada are due to wild bird introductions, likely from bird feces being tracked into the barn on dirty boots. The remaining 15 per cent could be from lateral transmission, he said. That minority matters, especially in regions where farms are closely spaced and where time and distance cannot act as buffers. 

The science behind lateral spread points to a range of possible vectors, including dust, feathers and aerosols, which can be carried by wind, he said. Rodents and insects such as flies can travel between barns, and human-mediated risks remain a constant.

However, quantifying airborne risk is a difficult task. During the major H7N7 outbreak in 2003 that affected 255 flocks and led to the culling of 30 million birds in the Netherlands, Dutch epidemiologist Armin Elbers said there were indications that farm proximity may have played a role in disease transmission between closely situated farms. Many farmers certainly believed this to be the case. 

“There is a definite tendency of poultry farmers to blame airborne transmission of diseases,” says Elbers, who pointed to biosecurity breaches as one among other possible causes. Farms situated in close proximity are more likely to see more visiting neighbours, he said. In some cases, virus may be passed on by family members who farm nearby and share equipment.

Elbers also wanted to know the role of airborne transfer of contaminated fecal droppings of wild birds during outbreaks, so he conducted a study to evaluate small particle samples taken from ventilation system air inlets. 

“We did a risk analysis,” he says. “It indicated that the daily probability of infection of a single poultry farm via aerosolization of contaminated feces from wild waterfowl is extremely low.”

Today, Elbers said farm-to-farm transmission is rare in the Netherlands– even in high density areas. Farmers learned the importance of strong biosecurity in 2003. They also learned about the importance of clear and quick communication. The Dutch have adopted a system they call ‘bucket sampling’ whereby farms in densely populated regions within a one-kilometre radius of an infected farm sample and test dead poultry for avian influenza on these still uninfected farms. With that, proactive culling is no longer a first response in densely populated regions.

Elbers doesn’t consider proximity to farms the main factor in introduction of bird flu on poultry farms in the Netherlands, but proximity to risk factors. It could be a neighbour borrowing equipment, or it could be proximity to waterways and grasslands that is an attractant for wild waterfowl. On this last front, researchers have mapped out high risk areas in The Netherlands, most of them in coastal regions.

“Complying to biosecurity measures is an important way to keep pathogens from entering a farm, but it’s also the most difficult to do, to consistently comply with every day,” he says. “It has to become a way of life for the farmer – and that’s very difficult.”

Canada’s regulatory blind spot

Despite mounting biosecurity pressures, Canada has no national rules governing how far poultry barns should be spaced to reduce disease risk. Instead, siting decisions fall under a patchwork of municipal and provincial policies, most of which focus on odour, manure management or environmental buffers, not pathogen control.

According to Manon Racicot, Canadian Food Inspection Agency (CFIA) veterinarian and epidemiologist, barn proximity doesn’t fall under CFIA’s purview. Besides, as others have pointed out, several factors impact how avian influenza spreads between farms, including farm practices. 

“It seems clear that farm density in the Fraser Valley has an impact on the infection rate, considering that 12 per cent of Canadian farms are located in British Columbia and that more than 50 per cent of highly pathogenic avian influenza outbreaks in commercial farms have occurred in BC,” she said. With approximately 600 commercial farms located mostly in a 100-kilometer stretch of Fraser Valley, BC has the highest farm density in the country. 

Proximity and density do not necessarily predict infection, though, Racicot said. “Since 2022, 150 commercial farms have been infected in B.C.,” she says. “With the establishment of primary control zones, the CFIA monitored an additional 439 commercial farms in the same region, and these farms remained negative for avian influenza over the past three years, despite high farm density and sometimes proximity to an infected premise.”

Vaillancourt worries, however, that Canada’s lack of regulatory guidance around barn proximity leaves the industry exposed, especially for high-value breeder operations. “They can follow all the national standards, but those standards were never designed to protect breeding stock,” he says. “They’re the basics.”

The 2012 Ontario court case involving Hybrid Turkeys underscored the limits of relying solely on federal biosecurity protocols. While the new breeder barn met regulatory requirements, Vaillancourt argued it still posed an unacceptable risk. No rules prevented its construction – just 800 metres from the great grandparent facility.

More than a decade later, that legal gap still leaves breeding farms vulnerable. In the absence of government-led planning, it’s often up to individual producers to assess siting risks, sometimes without the data, tools or authority to push back. “We’re not planning ahead,” Vaillancourt says. “We’re always reacting.”

Italy prioritizes proximity

While Canada continues to rely on a patchwork of local regulations, countries facing similar disease pressures have taken a more centralized and proactive approach. In Italy, for example, rules governing the distance between poultry farms have evolved in response to recurring avian influenza outbreaks. Francesco Galuppo, who works in animal health for the Italian government, explained that proximity rules were not initially part of national disease control strategies. 

Regulatory changes came in phases. The first major step was a zoning framework introduced in May 2023 following major outbreaks in 2022, which defined high-risk and surveillance zones. The second was the adoption of strict minimum distances between poultry farms. Farms of over 250 birds are divided into high-risk A and B zones. The rules do not apply to farms with fewer than 250 birds. In both zones A and B, minimum distance is set at 1.5 km, but in B zones no derogations are allowed. Derogations are permissible in A zones. Additional minimum distances are required between poultry farms and pig farms, as well as biogas plants.

While these rules already loosely applied in poultry-dense regions like Veneto, Lombardy and Emilia Romagna – where 70 per cent of Italian poultry production occurs – they now apply nationwide. In densely farmed areas, farmers looking to upgrade are unlikely to receive permits. In Canada, such a system could put farm families out of business. But in Italy’s cooperative-style sector, most farms work for the same company. “What we have is really adapted to the situation we have,” Galuppo says. 

Who should lead?

When it comes to barn proximity rules, Vaillancourt said the federal government is unlikely to lead. He believes the poultry industry is best positioned to define siting standards based on production type and disease risk. “It has to be industry-driven,” he said. “If it’s not the industry, it won’t happen.” Government’s role, he adds, should be to support enforcement once standards are in place. He pointed to pork as an example. “Swine has been better at this,” he says. “You don’t build next to a nucleus herd. You just don’t.”

As producers continue to grapple with avian influenza, the question of barn proximity remains unresolved in Canada. Distance isn’t a guarantee, but it can be a critical buffer when biosecurity fails. With no national rules and inconsistent oversight, siting decisions are left to individual judgement. Whether the industry will step in remains to be seen.