The owners of a Waikato egg farm remain puzzled by a blaze that ripped through two of its sheds on Tuesday, killing 50,000 hens.
The fire at Zeagold farm in Orini, east of Huntly, started at about 7.20am. It took 10 Fire and Emergency trucks to quell the flames, which destroyed two of the farm's 12 sheds.
Zeagold Nutrition chief executive John McKay called it a "pretty tough day".
"The first thing you're concerned about is your people, and thankfully the 12 people we had on site at the time of the fire safely exited the building and were unharmed," he told RNZ's Morning Report on Tuesday.
Attention then turned to the animals.
"We had an avian vet on site as soon as we were able to get people back on the farm yesterday. He has gone through with our people on the farm and looked at the birds. They seemed to be doing pretty well yesterday."
The facility is just a couple of years old, and was built to modern specifications - including cage-free housing for the hens and fire-retardant panels, which McKay said helped contain the fire's spread.
The cause remains a mystery.
"That's the puzzling thing with this. Obviously it's a new build, it's fully compliant. We'll have the Fire and Emergency inspector back on site with us later this morning, and just going through that. At this stage, we still don't know what caused the fire."
Until they do, he said it was not clear if the fire could have been prevented.
"It's very, very rare to have an incident like this - particularly in new buildings. That's why we've got to get into this investigation."
McKay said the loss would not contribute to the nation's ongoing egg shortage.
"It was devastating for us in terms of the loss of 50,000 hens, but when you put that in the context of the national flock of laying hens, it's only 1.4 percent of that population.
"So look, it was a devastating loss yesterday - it's not a significant number that have come out of the national flock."
Internationally eggs are in short supply, thanks to avian flu wiping out stocks and the war in Ukraine pushing up prices for energy and animal feed.
Locally, there has also been the 10-year legislative transition away from caged eggs, and the supermarkets duopoly's decision not to buy eggs sourced from colony cages, which took many farmers by surprise.