KOLKATA (Reuters) - Authorities in eastern India onWednesday started culling thousands of chickens, fearing thespread of bird flu in another district after a fresh outbreakin poultry this month.

About 1,000 chickens in a state-run poultry farm in WestBengal state's Malda district died in the last few days,prompting authorities to examine blood samples, officials said.

"We have decided to slaughter all the remaining chickens inthe farm," Anisur Rahaman, West Bengal's animal resourcesminister, said. An outbreak of the virus was reported inneighboring Murshidabad district earlier this month.

Poultry sales in the eastern state dropped by about 70percent since the avian flu hit in January, officials said, butit has had limited impact elsewhere in the country.

India has not reported any human bird flu cases so far.

"We will go for mass culling as soon as we get officialconfirmation," the minister said.

The strain of the latest virus was still being tested, butRahaman said preliminary checks have indicated the H5N1 strain."We think it is the deadly bird flu virus."

Earlier this month the outbreak, the fifth in India since2006, was reported in two villages of West Bengal's Murshidabaddistrict, prompting authorities to start culling chickens afteralmost a month after they claimed to have contained the virus.

Officials say the virus could have originated fromneighboring Bangladesh, struggling to contain a massiveoutbreak.

In January, the H5N1 virus affected 13 of the state's 19districts, including Murshidabad.

Around 3.4 million birds were culled during the lastoutbreak, which the World Health Organization (WHO) describedas the worst-ever in India.