The avian influenza outbreaks in south-eastern Australia have caused some gaps on supermarket shelves and prompted temporary buying limits.
To date, most outbreaks have been confined to egg farms. Only one meat farm has been affected and there are no reported shortages or buying limits on chicken meat.
But experts warn the outbreaks could continue, and the financial impact on egg farmers, who are still paying off the clean-up costs for the last high pathogenicity avian influenza (HPAI) outbreak in 2021, could be severe.
This is what you need to know.
Is there an egg shortage?
There are fewer eggs, and you may have noticed fewer cartons on shelves.
Australia takes a zero-tolerance approach to HPAI outbreaks, which means the protocol after any reported infection is the euthanasia of all birds on the farm. The avian influenza outbreaks in Victoria, New South Wales and the ACT have resulted in the destruction of about 2 million chickens.
According to peak body Australian Eggs, the reported losses – and not all jurisdictions have reported up-to-date numbers – represent about 7% of the national flock of more than 20 million laying hens.
Rowan McMonnies, the managing director of Australian Eggs, says the losses are “significant and causing disruption” but that “most suppliers are able to fulfil contracts”.
“The recent avian influenza outbreaks have caused significant disruption but there are still over 21 million chickens laying eggs every day and the community can take comfort that nation-wide supply has not collapsed,” he said.
Both major supermarkets have said they are experiencing temporary delays in NSW, Victoria and the ACT. Woolworths introduced a two-carton limit in those three jurisdictions last Thursday 27 June. A spokesperson for Woolworths said the short-term delay was due to the temporary closure of an egg-packing shed which adjoins one of the affected farms, and they are expecting supply to recover toward the end of the week.
“Right now, the majority of customers are only buying one carton of eggs at a time, and there’s no reason that should change,” the spokesperson said. “We encourage shoppers to be mindful of others and continue to only buy what they normally would.”
Coles has had a two-carton limit in every state except Western Australia since 9 June.
Other retailers also moved to limit their sale of eggs after the ACT case last week, and the subsequent impact on the packing shed. McDonald’s temporarily shortened its breakfast menu hours to wrap up at 10.30am, instead of 12pm.
Importantly, all three companies have a commitment to free-range eggs. McDonald’s only uses free-range eggs in its products. Both Woolworths and Coles have stopped selling cage eggs under their house brands and have committed to phase out all cage eggs by 2025, so many of their suppliers are also free range. All the farms affected by HPAI outbreaks so far have been free-range egg farms, with one a mixture of free range and caged eggs.
Why is it affecting free-range egg farms?
HPAI infections in commercial flocks come from interactions with wild birds, mainly ducks. It can also be passed by contaminated faeces or other material.
McMonnies said free-range production systems are more exposed to the risk of avian influenza because of the increased opportunity for coming into contact with wild birds.
“Wild bird spillover of avian influenza is one of a number of biosecurity threats to commercial farms and can still impact barn and cage systems through contact with vehicles and equipment,” he said.
Third-generation egg farmer Brian Ahmed operates a 30,000-bird caged egg farm on the outskirts of Melbourne. He says free-range production systems will always be more vulnerable and that’s why Australia needs a mix of cage, barn, and free-range producers.
Last year, Australia’s agriculture ministers made a commitment to ban cage eggs by 2036, in response to decades of consumer pressure.
Dr Michelle Wille, a senior research fellow at the University of Melbourne, said managing HPAI risk in free-range flocks is “a real challenge”.
“Free range is a good thing for animal ethics but biosecurity becomes extremely challenging as its very hard to prevent wild birds interacting with poultry which are outdoors,” she said.
Is this the virus that’s causing problems overseas?
There is a global outbreak of a strain of bird flu identified as H5N1, which has not yet been detected in birds in Australia, although its arrival is considered inevitable.
The current outbreaks in Australia are different strains. The H7N3 strain was detected at an egg farm near Meredith in western Victoria in May, and has since spread to every other egg farm in the area – that’s seven infected properties in total. Another property at Terang has been infected with the H7N9 strain. It was connected via contact tracing to the first Meredith property.
Two farms in the Greater Sydney Basin – one egg farm and one meat farm – last month reported the H7N8 strain. And last week the H7N8 strain was detected at a commercial poultry farm in the ACT.
One possible reason for the confluence of outbreaks is the triple-dip La Niña that Australia experienced in 2020, 2021 and 2022.
Australian research published in 2021 analysed avian influenza outbreaks dating back to 1970 and found the risk of an outbreak in poultry farms increases after periods of high rainfall, with the peak risk two years after the onset of the high rainfall period. That’s due to waterfowl breeding on temporary wetlands. When the temporary wetlands dry up, large numbers of young, “immunologically naive” birds retreat to more established waterways, and that concentration of juvenile birds with no immunity increases avian influenza prevalence in wild flocks.
And the higher the rate of low pathogenicity avian influenza in wild flocks, Wille explains, the higher the risk of spillover to commercial poultry farms, where it then evolves into high pathogenicity avian influenza or HPAI.
University of Western Australia associate professor Parwinder Kaur, the director of DNA Zoo Australia, said that if H5N1 reaches Australian wild bird populations at the same time that H7 viruses are circulating, there is a risk that the two strains could mix in the same commercial flock. If two strains inhabit the same host, Kaur said, something called an “antigenic shift” could occur, which would be the creation of a new strain of the virus.
What about the farmers?
Australia’s commercial poultry producers are still paying off the cost of cleaning up after the last HPAI outbreak, which occurred in the Meredith-Lethbridge area in 2020-2021.
The destruction and disposal of potentially infected birds and the cleanup of properties is conducted by state agriculture departments, covered by a levy which is added on to the cost of buying new chickens. As of July 2021, the Emergency Animal Disease Response (EADR) levy is 1.1c per laying chicken. Added to other levies, the it totals 15.27c per bird.
There are only two suppliers of commercial laying chickens in Australia, as the genetics are tightly controlled. They are distinct from the chicken breeds used by back yard chicken owners.
McMonnies said the EADR system reduces the cost of disease outbreaks.
Farmers who have to euthanise their birds are compensated for their value at the time of death, but that is usually less than the replacement cost. A new layer may cost $20 and produce eggs for 12 to 15 weeks, but a hen which has been laying for 10 weeks already will be valued lower because they have fewer productive weeks remaining.
Back yard poultry owners have been urged to keep their birds confined or otherwise separated from wild birds to reduce the risk of infection.