Tamworth poultry giant Baiada has won approval to double the size of its Westdale chicken facility, in a project the proponent said would establish the region as a "poultry cluster".
Once the $203 million project is built, the processing facility will employ an additional 679 staff.
The construction period alone is estimated to be worth an additional $658 million to the local economy.
The Department of Planning Industry and Environment signed off on the project, which was deemed of state significance, on Friday.
The upgraded poultry facility will have the capacity to process three million chickens a week, double the existing facility, which can process 1.3 million. It will operate every day, around the clock.
The project will also allow Baiada to close their existing West Tamworth facility on Out Street.
The project's environmental impact statement (EIS) reveals the project will put hundreds of millions of dollars into the pockets of local farmers.
That's because the tens of millions of new chickens will eat an additional 546,000 tonnes of grain a year, most of which will be sourced locally.
"A key component in the development of the Tamworth region as a poultry cluster is the availability of local grain from farms in the region to produce poultry feed blends while minimising transport costs," it said.
"As per current operations, grain for the expanded operation will be primarily sourced from the surrounding areas ... the economic benefits from the increase in regional grain supply are estimated to be [about $136.5 million]."
The project would also spur the construction of 300 local broiler sheds to supply the plant once it is operational.
Baiada already employs 1,029 workers in the Tamworth area,
The project's DA received just one submission, with an anonymous resident opposed to the upgrade.
They said it would be ugly, smell, use scarce water and devalue neighbouring property, among other "significant detrimental" effects.
It comes after Fairglen Farms Pty Ltd last week applied to Tamworth Regional Council for approval to spend $16 million doubling the size of an existing chicken farm in Manilla.
The new facility will replace Baiada's processing plan in West Tamworth, which will be closed down.