MINNEAPOLIS (AP) - Minnesota's state veterinarian has broached the possibility that bird flu may be spreading from farm-to-farm in the state's top turkey-growing counties.

Experts downplayed that possibility in the early days of the outbreaks, which have cost Minnesota poultry producers more than 5.5 million birds. They said instead they suspected the virus was being carried by waterfowl that would spread it via their droppings, then tracked into barns by people.

State Veterinarian Bill Hartmann says there's still no confirmation of lateral spread. But he says industry veterinarians now suspect the virus may be spreading that way. He says there's still no hard evidence.

While farm-to-farm spread might explain why so many farms in Kandiyohi and Stearns counties have been affected, Hartmann says it might be because those counties have so many farms.