Bird flu killed around 5,500 chickens in Purbalingga district, Central Java, during January 2010, ANTARA quoted a local official as saying. Some 5,000 dead chickens were found at Tumanggal village and 500 at Pasunggingan village, both in Pengadegan sub district, Purbalingga, Hartono, head of the Purbalingga animal husbandry office, said here on Monday. The local authorities have conducted measures such as insecticide spraying, rapid test and vaccination to prevent the bird flu or H5N1 virus from spreading to wider areas. Last year, there were four cases of bird flu and around 6,000 chickens were killed by the virus.