STORY: :: FileBrazil on Wednesday declared its commercial flocks free of the bird flu virus after observing a 28-day period without any new commercial farm outbreaks, the country's ministry of agriculture said.The world’s largest poultry exporter began its countdown to disease-free status on May 22 following the complete disinfection of the farm where Brazil’s only commercial outbreak was detected last month.China and other importers banned chicken imports from Brazil, which accounts for 39% of global chicken trade, pending measures to control the disease.Agriculture Minister Carlos Favaro says Brazil is trying to resume exports with its trading partners.The World Organization for Animal Health must now confirm Brazil's status, according to guidelines.Brazil's first outbreak hit a chicken breeder farm in the town of Montenegro, where 17,000 birds were culled.