Rainbow Valley Turkeys is planning to develop a new complex at Slaty Creek near St Arnaud, including breeder and rearing sheds and office buildings, reports ABC News.

Northern Grampians Mayor, Bryan Small, says the company is now Australia's major breeder turkey supplier and is now developing markets overseas.

He says the application attracted only a few objections that have been successfully mediated, and the council had little hesitation in approving it with about 50 conditions.

"It's not far from St Arnaud, but it is in an area that's very satisfactory for this sort of development," he said.

"We have no affected land-holders in the area, the area is very good from the point-of-view of native vegetation removal, there's not much of that to be done and it's off the main road."