Around 22,580 chickens had died of bird flu (Avian Influenza - AI) virus in Indonesia's East Java Province from January to September 2007, a local official said.

The AI virus-infected chickens were mostly from back-yard farming, Antara news agency quoted Bambang Hermawan of the East Java provincial animal husbandry service as saying on Friday in Surabaya, capital of East Java province.

The dead chickens were found in 25 districts/towns in the province, said the official.

The East Java authorities have carried a number of measures to prevent the spread of bird flu virus.

Indonesia is one of the worst-hit countries in the world by bird flu. Bird flu has killed 85 people out of 106 affected persons in the country.