The virus was not found anywhere else, and is believed to have spread from wild birds to free-range laying hens foraging outside.
Mainland Poultry chief executive John McKay said repopulation efforts had been going well since the farm was given the all-clear in April.
“We’re really pleased with how it’s going.”
Chickens were being reintroduced in a staged process, with the first flock ready to start laying in the next two weeks or so.
Day-old chicks were being brought into the rearing sheds and kept there for 15 weeks before being transferred to each of the eight laying sheds.
“It’s great to see birds back on the Hillgrove Farm,” he said, adding that it was a huge relief for the team, who had faced a tough few months.
It would allow staff to “get back into some sort of normal operations and normal routines”.
The farm was on track to be fully repopulated by May next year.
McKay said the recent biosecurity agreement reached by chicken farming groups and the Government was good news and had “landed in a good place”.
The agreement covers cost-sharing arrangements between taxpayers and the poultry and egg industries.
“It was unanimously supported by our members on the egg side and also the broiler side of the industry,” McKay said.
It followed a “detailed and constructive process” worked through with the Ministry for Primary Industries and the Government.
Under the agreement, the industry is set to pay 45% of poultry disease readiness costs, such as planning, training and research.
It will also cover 45% of response costs - or 40% for bird flu - and measures include testing, communications and control measures.
Mainland Poultry was still working through the compensation process with MPI, which won’t be completed until the farm is fully repopulated.
- RNZ