Bangkok - Thailand has detected a fresh outbreak of avian influenza among free-range chickens in the northern province of Sukhothai, the country's agriculture minister confirmed Monday.

Agriculture Minister Somsak Prissananathakul said lab tests had confirmed that a dead chicken from a family farm in Thuang Saliam district of Sukhothai province had died of an infection with H5N1, the virus subtype causing bird flu.

All 17 free-range chickens on the farm were culled and the area in a one-kilometre radius of the farm declared a flu-outbreak zone, said Somsak. Altogether 200 birds were culled in the district.

It was the third confirmed outbreak of bird flu detected in Thailand this year.

Thailand's chicken industry was hard-hit by the aviation influenza pandemic that affected much of Asia in 2004 and 2005.

At the peak of the epidemic in 2004, some 25 Thais were infected by the virus, 17 of whom died.