The Otago egg farm that sat at the centre of New Zealand’s first outbreak of highly pathogenic bird flu is back to a full flock, with about 200,000 hens once again living in its sheds roughly 18 months after every bird on the property was put down.
Mainland Poultry’s free range farm at Hillgrove, near Dunedin, was placed under movement controls on 2 December 2024 after testing confirmed the H7N6 strain of high pathogenic avian influenza. It was the first time the virus had been found in this country, and the response was swift and brutal. About 200,000 chickens were humanely euthanised and buried in a secure landfill, along with the eggs, litter and manure that could have carried the disease beyond the farm gate.
Now the sheds are full again. Mainland Poultry chief executive John McKay told RNZ that the rebuild was complete. “So the farm is fully repopulated across both our rearing sheds and our laying shed – 200,000 birds back on farm,” he said. The property is now producing in the order of 150,000 eggs a day, a steady return to the kind of output that had been wiped out overnight when the virus was found.
Getting there took patience. Repopulation began in April last year, and because day-old chicks spend about 15 weeks growing in rearing sheds before they are ready to move across to the laying sheds, the farm could only be rebuilt flock by flock. The final birds were introduced over the past month, closing a long and careful process that started with empty, disinfected buildings and a property that had to prove it was clean before any new animals could arrive.
McKay had described an earlier stage of that rebuild as a turning point. When the first hens began laying again, he told the New Zealand Herald in September that it felt like a milestone after a grim year. “This is the light at the end of the tunnel,” he said at the time. “The rearing sheds are full, our first birds are moving to our laying sheds and we just got our first eggs off the farm.”
The Ministry for Primary Industries, which led the biosecurity response, says the H7N6 strain was never found anywhere outside the Hillgrove property. That containment was the single most important outcome of the operation, given how quickly the disease can move through poultry and how heavily other countries have been hit. With the farm running normally again, the formal response is being wound down. MPI Assistant Commissioner for Compliance and Response Angus McKay said the work was moving into its final phase. “With eradication achieved and the property fully operational again, the response is now transitioning to close-out,” he said.
How the virus arrived has shaped the lessons the industry is taking from it. Testing indicated that the infection began when free range laying hens foraging outdoors were exposed to a low pathogenic form of the virus carried by wild birds. Inside the flock, that milder virus mutated into the high pathogenic strain that forced the cull. It is a reminder that the open paddocks valued by free range customers also bring birds into closer contact with the wild waterfowl that move avian influenza around the globe.
For Mainland Poultry, the response has been to lean harder on the basics. McKay said the company was watching outbreaks overseas closely and applying what it learned at home. “We’re learning constantly from what’s happening around the world,” he said, adding that protection “really comes down to thorough and rigorous on-farm biosecurity”. That means tighter controls on who and what moves on and off the farm, careful management of the points where hens and wild birds might cross paths, and constant monitoring for any sign the virus has returned.
The cost of the response was significant. The Government allocated about 20 million dollars to cover the eradication effort, and a compensation process for the business is still being worked through, with the figures treated as commercially sensitive. MPI has used the case as a template for how it would handle any future incursion, including the far more dangerous H5N1 strain that has devastated flocks and spread to mammals overseas but has not been detected in New Zealand.
The timing of the outbreak made it sting all the more. It landed while shoppers were already feeling the pinch of an egg shortage, the product of a separate shift away from colony cages that had pulled hundreds of thousands of laying hens out of the national flock. Losing one of the country’s larger egg operations for the best part of a year did nothing to ease that squeeze. A fully restocked Hillgrove laying around 150,000 eggs a day puts a meaningful amount of supply back into the system, even if the wider rebalancing of the industry is still working itself through.
For now, the headline is a simple one. A farm that was emptied out and sealed off as a biosecurity emergency is once again full of hens, the disease that put it there has been stamped out, and the eggs are flowing again.
What do you make of how New Zealand handled its first bird flu outbreak, and the move to free range and away from cages? Share your thoughts in the comments below.
This article was written by AI, briefed to report the facts, hopefully without some of the bias people bring to the job 🙂
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