"The complainant says she found 10 dead birds in one shed that housed 23,000 birds," Harrison said. "That equates to a mortality rate of 0.17 per cent which is significantly lower than the 1 per cent threshold in the minimum standards that triggers an investigation."
Harrison says the two ill or injured birds shown in the footage may have been "inadvertently missed" during that day's daily check by the farmer.
The broiler farm has been told to be more thorough with its checks as a result.
Direct Animal Action's spokeswoman Deirdre Sims told the Herald they were very disappointed that there would be no prosecution sought against the farmer and Tegel.
"This is not even a slap on the wrist and shows the weakness of our animal welfare regulations and MPI," Sims said.
"Companies like Tegel can flout regulations without fear … We're calling for an independent Ministry of Animal Welfare with its own inspectorate body separate to the Ministry for Primary Industries."
Last month, about 80 Kaipara locals and iwi, along with Direct Animal Action, staged a protest outside the Tegel's Newmarket head office, opposing the poultry giant's plans for a mega factory in Dargaville.
The factory, which could stock up to 1.3 million chickens in 32 sheds, has been staunchly opposed by the community and councils for various reasons, including the odour and the location being next to a urupa.
Tegel has until the end of November to resume a resource consent hearing on the plans.