At least 15,000 chickens killed at Pak farms

Workers killed 15,000 chickens in northwestern Pakistan after poultry at two farms tested positive for the H5 strain of bird flu, an official said on Tuesday.

The chickens were asphyxiated with carbon dioxide in plastic bags and then buried, said Arbab Shahrukh Khan, a senior agriculture ministry official.

Officials said this week they doubted the birds were infected with the deadly H5N1 strain of bird flu.

One farm was in Charsadda, near Peshawar, the capital of North West Frontier Province. The other was in the hill resort city of Abbottabad.

Pakistan hasn't reported a case of H5N1 in the past two years. But in 2003, between 3 million and 4 million chickens were killed after an outbreak of the H7N3 strain of bird flu.