By Bonnie Flaws

The Hillside Farm bird flu outbreak continues to cost poultry exporters, with only 65% of trade recovered. Yet no detailed risk benefit analysis was done before the decision was made to cull 200,000 birds or halt exports.

A sociologist who specialises both in agribusiness and the production of scientific knowledge says the government’s current bird flu policy is an existential risk to New Zealand’s farming sector, largely because there is no financial safety net for producers who are ordered to cull their birds in  the face of a high pathogenic avian flu strain that becomes endemic.

Jodie Bruning fears that locally owned poultry (which includes eggs) businesses would then be vulnerable to offshore capital looking for a bargain, as banks would step away from supporting businesses, while the costs of insurance could become prohibitive.

The risk from the H7N6 strain may have been overstated. Bruning believes that authorities jumped the gun and raced to act regardless of the death toll and the role of herd immunity.

H5 avian flu strains are already found across some 400 species including cattle, and there is little risk to livestock or humans. Prior infection is known to reduce the risk from a high pathogenic strain.

The United States recently found that mass culling operations did not ‘stamp out’ H5 HPIA strains. And so from her perspective, the biggest risk is the Ministry for Primary Industries not doing the work to establish the death rate and sentencing farms to economic death based on infectivity.

But criticisms don’t stop there. Speaking to RCR on April 29 Jodie Bruning, who was in the digital interview chair alongside former WHO epidemiologist David Bell, said the risk from bird flu was both hypothetical and overstated.

“I think we need to look at the context here … [culling is] the only thing MPI knows how to do.”

Controls lifted at Hillside Farm

In the last two weeks a few thing have happened.

Firstly, RCR received a response to an OIA request we put to MPI in December when the bird flu outbreak at Hillside Farms was announced.

Secondly, Biosecurity Minister Andrew Hoggard told the media that Bird Flu is the biggest biosecurity threat facing the country, and finally, MPI formally announced it has lifted controls at Hillside Farm.

Bruning noted that it had taken MPI four months to respond to our questions – really only once they were ready to announce the end of the outbreak -but there was no good reason why the data they had collected and used to justify its response could not have been published in a report long before now.

Poor marks for transparency.

Biosecurity rationale

Right from the outset RCR had wanted to find out what MPI’s rationale was for the approach it was taking, as well as what testing regime was used and what cost benefit analysis had been done before taking the course of action that it did.

Was it warranted? After all, there were many unanswered questions about the management of and policy response to Covid 19.

In the end, MPI reported that a total of 200,000 birds were culled, and while the farm was fully compensated, there have been major financial losses involved for poultry producers faced with temporary access to export markets restricted.

RCR invited Bruning and Bell to be interviewed on the topic, and asked them to review the OIA response.

Listen to the full interview on the RCR website or app.

OIA response

MPI said that it was accepted practice internationally to depopulate flocks to stop the spread of the virus. But Bruning queried: since when?

“This is an ancient virus, so this is a moot point. Then they say the mortality rate from HPAI can be as high as 100% of birds. Well, we would like to see the data on that please.”

What the OIA response revealed was that:

• As at 2 December 2024, approximately 10,000 birds at the affected property were considered to be sick, and approximately 3500 had died – a very small percentage of the total flock
• symptoms included reduced egg production, death, digestive issues, and being quiet and hunched, but no clear respiratory or neurological signs
• PCR tests used to identify avian influenza ran for 45 cycles – this is considered extremely high, as thresholds above 35 and can result in false positives
• PCR tests for sick and carrier animals run between 20 and 45
• suspension of poultry exports was required by trading partners after the H7N6 detection
• no detailed risk-benefit analysis was done
• 65% of affected trade has since been recovered

MPI concluded that the virus mutated into a high pathogenic strain in the Hillside Farm shed, which means it wasn’t an HPAI from the outset:

“Testing indicates that the infection at the Hillgrove farm happened after free-range laying hens foraging outside were exposed to the low pathogenicity virus from wild birds, which then mutated in the hens to become HPAI. It was the first detection of HPAI in New Zealand.”

In a follow up article on her Substack, Bruning questioned how the virus appeared to naturally mutate into a high pathogenicity strain, querying whether feed or nutrient stress may have been a cofactor. She says the most likely reason would be stress.

“What if key dietary ingredients such as amino acids were at the wrong level? So much can go wrong. Getting to the bottom of this involves deep trust, with our businesses confident that MPI isn’t going to walk around swinging sledgehammers,” she said on Substack.

Bruning pointed out that MPI had to transparently declare to importing nations that there was an HPAI, but that they didn’t necessarily have to bow to any off-shore authority and engage in automatic mass culling.

“Because clearly, not all the birds were dying.”

In her Substack article, she asked:

“What if HPAI is in a flock but only 20% of the flock die, and the rest recover? Is that fair on the farmer, that the entire flock is culled? Is it fair on consumers who then face egg shortages, and egg price hikes? Word on the street [from talking to poultry farmers in the know] is that perhaps only 6000 had died out of 80,000. Would this have made the strain a low pathogen avian influenza (LPAI)? ….

“I want to know exactly what guidelines and what data makes a virus an ‘HPAI’ virus – and the work our authorities go to, to establish the pathogen of concern reflects those characteristics. MPI should have an obligation to publish these plans and the data supporting them, prior to any cull order. Organisations that have to cull should never be required to sign non-disclosure agreements.”

How did authorities deal with bird flu historically?

Historically, Dr David Bell said, “we just got on with it. This is a little bit like Covid has gone away and people need something else to worry about.”

He went on to point out that while it’s a significant problem for birds, actually bird flu is “a tiny problem to humans”.

Furthermore, the risk with the current approach to managing bird flu was that culling is effectively a way of breeding out the more resilient chicken from the flock.

“If you kill everything rather than keeping a breeding stock from the ones that survive, you are not keeping the stronger genetic stock.”

PCR testing

Another issue revealed in the response was the less than systematic approach to testing, and also the inappropriate use of PCR.

MPI admitted that they could have tested the same bird more than once:

“As at 3 December 2024, 35 samples had been taken from the affected property, and 94 percent of these had returned positive results for high pathogenicity avian influenza (HPAI). Please note that a given bird may be represented in multiple samples.

“MPI does not record which specific birds within the shed were sampled or how many birds are represented in the samples, so the number of birds that tested positive for the H7N6 strain of HPAI is not known.”

Bell said it was surprising that that they were not more systematic, so they could get an idea of what percentage of the flock was testing positive.

It was important to label samples and follow a chain so that you know which chickens gave which samples and how many samples came from individual chickens – especially if they are then going to kill a couple of hundred thousand birds and put the farm’s economic viability at risk, he said.

MPI advised us that the PCR tests used to identify avian influenza ran for 45 cycles:

“Generally, a PCR result from samples collected from sick or carrier animals will have a cycle threshold value between 20 and 45, which was the case for the samples taken from the affected property,” the OIA response said.

But Bell said this meant there was a high likelihood of false positives – the cycle threshold was too high to give meaningful results.

“What they should do is tell [us] the number of cycles of the actual positive results, to avoid the possibility that it’s showing up background contamination.”

Bruning noted that PCR at these high thresholds can also detect dead virus from a previous infection.

Natural immunity approach in the US

Bruning noted that in the US, 166 million birds were culled over four years as a result of H5N1 avian influenza. The virus appeared to have cycled through naïve flocks repeatedly, which were then culled. The virus was not permitted to die down naturally. The US then changed tack in response to skyrocketing egg prices.

Bruning noted in her Substack piece that while the USDA was not front-footing a conversation about natural immunity as a way of moving beyond a cycle of repeated flock infections, the suggestion was implicit in the change of approach.

USDA halted its aggressive culling and also acknowledged that vaccines have not been successful in stopping transmission in poultry, and therefore rejected it as an option.

H5N1 could pose an existential threat to farmers with current approach

Bruning warned that if the H5N1 strain were to arrive from Antartica, it would be declared endemic and there would be no financial compensation for farmers.

Yet H5 strains were known to infect hundreds of species and have historically presented little risk to humans. An absurd situation could arise where MPI was testing all the (asymptomatic) cows in New Zealand to find this virus.

If poultry producers were then ordered to follow the “kill the whole shed no matter what” approach, it was unlikely that any bank would fund support loans for producers

“It could mean the whole industry falls over because they can’t assure their income for the next six months,” she said.

Furthermore, there were certainly offshore firms standing by to scoop up locally owned producers at rock bottom prices.

“I have an enormous concern about how we retain New Zealand owned businesses here … this is why farmers all over New Zealand are extremely anxious.”

Institutional knowledge

She urged MPI to look at the real experiences of farmers and the knowledge they held – for example, the indication that farmers are far more likely to get sick when they’re culling the shed than from letting an infection travel through the shed and maintaining good biosecurity and hygiene practices.

The poultry industry has institutional knowledge on past events that can inform MPI and ensure that all rules and instructions are practical and reasonable for the industry here. MPI can’t assume every HPAI strain is horribly lethal and cull based on a suspicion, she said.

“We can’t trust that offshore agencies know more than our poultry industry. The industry needs to step up, they need to assert themselves, they need to look at what they have been doing for 200 years. That information needs to become public. It can’t just be MPI walking in and pretending they have the science.”

She also said we should know the extent of expertise on avian influenza within MPI and how that compares with the expertise that is reflected by what farmers and operators know from practice.

Global pandemic industry

Bell was concerned that a huge industry had now grown up of people who were paid to talk about the risks of viruses. Particularly the lie that we are now more at risk than ever before.

“[Viruses] are less risk than they used to be but we have thousands and thousands of people internationally who are paid to play up this risk because that’s their job. And this is where it is leading us.

“It’s taking us down an irrational path that has huge economic consequences. Rather than killing huge numbers of birds New Zealand could actually show that there is a much better way of dealing with the problems like this, which as Jodie said, is how we have health [living alongside them] for the last few hundred years.”