Police tape and warning signs are seen outside a duck farm in Nafferton, northern EnglandA third outbreak of avian flu has been detected in Washington state, prompting agriculture officials on Tuesday to warn bird owners to keep their flocks away from migratory birds that have spread viruses from Oregon to British Columbia. State and federal agriculture officials culled about 120 backyard chickens, geese and ducks in Clallam County, 125 miles (200 km) northwest of Seattle, on Sunday after confirmed infections of the highly pathogenic H5N2 strain of avian flu. “All bird owners, whether commercial producers or backyard enthusiasts, need to continue practicing good biosecurity, preventing contact between their birds and wild birds and reporting sick birds or unusual bird deaths,” said U.S. Department of Agriculture spokeswoman Joelle Hayden. The virus has not been found in commercial poultry and there was no immediate public health concern, federal agriculture officials said. Most strains of bird flu viruses do not infect humans, although some strains can be dangerous or deadly. More