Cardrona Catchment Group chairman Mike Scurr, who manages Hillend Station in Cardrona Valley, said farmers from seven properties in the valley bought rabbit poisoning gear from the Otago Regional Council in 2017.
The farmers bought a carrot-cutting machine and a screening plant due to their "collective fear" of losing access to the gear after the council signalled it would no longer poison rabbits.
The screening stops small pieces of poisoned carrot being available for smaller animals to eat, such as birds and skinks.
Originally the plan was for the farmers to use the gear themselves to poison rabbits on their properties.
They soon realised the time-poor farmers needed specialist help and employed former council staff member Peter Preston.
Mr Preston, who operates Preston Pest Control, uses the gear to produce and distribute the poisonous carrots for the farmer-shareholder business Cardrona Valley Pest Control.
Now the business provides poisoned carrots to Mr Preston and any landowner or contractor in Otago and Southland who holds the certification required to undertake the control method.
Carrots are cut, put through a screening plant and laced with pindone poison. They are then scattered both by air or by using quadbikes in July and August each year when it is colder and less food is available for rabbits to eat.
Winters becoming shorter and warmer made it harder to control rabbit numbers, Mr Scurr said.
"Rabbits are now breeding almost 12 months of the year and our window of opportunity in the winter is shrinking."
The control method had been effective but landowners need to "continually stay on top of it".
"It is a major tool in our ability to maintain low rabbit numbers in the area."
Profits from the business are funding projects to control weeds and pests, such as wilding pine and nassella tussock, ferrets, pigs and rabbits.
The business provides carrots to up to 30 clients, including the original seven shareholders, who own 80% of the land in the valley.
Every remaining landowner in the valley has been invited to be shareholders in the business and many have accepted.
"All pest and weed control is only as good as your neighbours," he said.
