Associate Agriculture Minister and Minister for Biosecurity Andrew Hoggard. Photo: RNZ / Samuel Rillstone
Officials have not yet found any links between a second chicken farm that has been isolated, and a poultry farm where bird flu has been identified.
Investigations are underway at the second farm after hens started showing signs of illness and a number died, though it is not yet know what is making them sick.
This second property is a small free-range poultry farm south of Dunedin, "about an hour away" that is "unrelated and some distance away" from the first, but more precise details are not able to be released at this stage, Biosecurity Minister Andrew Hoggard told Checkpoint on Wednesday.
It had been been isolated as a precaution, and testing was underway.
The highly aggressive avian flu strain H7N6 was first discovered in New Zealand after sick chickens were noticed on an Otago Mainland Poultry farm at Moeraki, on Monday 25 November, and testing began there on Saturday 30 November. Officials have said the virus was likely contracted from wild waterfowl.
Second Otago chicken farm in isolation, testing underway
Culling of 80,000 birds was underway at the first farm, where birds in two separate sheds had tested positive. The farm has a ten kilometre buffer zone around it and restrictions preventing the movement of animals, equipment or feed.
The second farm was not a Mainland Poultry farm.
Test results were expected back on Wednesday night or Thursday for the second farm, for more of the sheds at the first farm, and for other Mainland Poultry farms, Hoggard said.
(On the first farm, the virus was first detected in shed 4, and birds in shed 3B had also been found to be infected. The tests still being carried out there are for shed 1 and 2, but the birds in shed one and two were showing "normal chicken behaviour" so far, Hoggard said.)
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Investigators were working on tracing whether any workers, contractors, visitors or equipment had been on both farms in the past three weeks, Hoggard said: "At this stage there's nothing obvious".
"The key rule here is you never make assumptions, you test, you find out the evidence, and then you rule things out, and you're left with what it is. We're taking a precautionary approach because there's sick birds, we've put restrictions in place, and we'll find out when those tests come back what the answer is."
After the first farm tested positive, six other 'at risk' farms were identified by officials, but this was not one of those, Hoggard said.
A second farm with sick birds was "a concern, but it's not unexpected", he said.
"But I'm thankful for the fact we've got onto this really early, that people are reporting it that there are signs. So I feel confident that other countries have demonstrated the ability to get on top of this strain quickly.
"We've had plenty of experience in the past with other bird diseases, being able to get on top of them."
After the the birds from farm one are killed, the carcasses and litter from the sheds will be loaded onto to trucks lined with leak proof plastic and taken to a Southland landfill, where they will be buried in a deep pit, designed with impermeable layers.
Hoggard said it would likely take "three - four days to get the job done."
"The team's working really hard."
Farms that suffer losses as MPI powers were executed under the Biosecurity Act could claim costs, he said, which would be determined in the aftermath. A previous example was dairy farms that had been able to claim for loss of milk production and feed, as controls against the spread of Mycoplasma bovis were enacted.
In a statement, Mainland Poultry chief executive John McKay said it was in "full response mode".
"Today we have begun the humane culling of birds in the two affected sheds at Hillgrove Farm. It is expected to take two to three days, using industry standard practice of CO2 containerised gas.
"This method is in line with the Code of Welfare. We will be taking every precaution to ensure the safe and secure disposal of chickens and waste materials from the affected sheds under the direction of the Ministry for Primary Industries (MPI)."
McKay said although necessary to stop the virus spreading, culling decisions were upsetting and it was a distressing situation for his team.
"As an industry, we have been preparing for this type of scenario for some time. Our proactive collaboration with MPI and the wider industry has allowed us to be ready and ensure swift action.
"Mainland Poultry remains committed to the welfare of its birds, the wellbeing of its staff and the responsible management of the situation. We will be doing everything in our power to eradicate the virus."