The bird flu epidemic has spread further in the Indian state of West Bengal with 13 of the state's 19 districts affected, officials say.
By Subir Bhaumik
BBC News, Calcutta
An outbreak has been reported from Budge Budge, a suburb of the capital, Calcutta, officials say.
A minister said that the situation was "alarming" Officials say more than 2.5 million birds would be culled.
The H5N1 strain of bird flu is regarded as highly pathogenic and can also cause disease and death in humans.
Health experts have warned that the outbreak could get out of control.
No cases of human infection have still been reported.
What is worrisome is that the flu is affecting the populous state capital, Calcutta.
On Thursday, tests on dead birds from Balagarh, less than a two-hour drive from Calcutta, tested positive for the disease.
Now, dead birds in Budge Budge, less than an hour's drive from Calcutta, have been found to be inflected.
"The situation is alarming," said West Bengal's Health Minister SK Mishra.
"We have done our best to check the epidemic but it is some task."
Tens of thousands of rural families, for whom poultry is a major source of income if not the only one, have been ruined.
Many more may face the same fate as the epidemic seems to be spreading.
Poultry farmers have been badly affected
State animal husbandry minister Anisur Rehman said the government had "some way to go" in culling the targeted 2.5 million birds.
He said that two-thirds of the target had been achieved.
"More culling teams are needed in all the affected districts but these are things that cannot be hurried. The men in the culling teams have to be quarantined first before they can be asked to start the operations," Mr Rehman said.
But there have been worrying reports that the government culling teams were using villagers to catch the infected birds to kill them.
"The government employees have protective suits but the villagers are totally exposed. They don't even have a pair of gloves, so it is dangerous to use them but that has to be done," said animal disease expert Debojit Brahma.
In many districts, the villagers had resisting culling of their backyard poultry - and that, experts say, may explain the spread of the virus.
"Poultry is a major source of income for the poor villagers. It is not unusual for them to resist culling. So we have to persuade them rather than force them," said Manasa Hansda, a senior official of Birbhum, one of the worst-hit districts said.
The problem is made worse because many poor and illiterate farmers are sometimes misinformed about basic hygiene.
Dead birds are reported to have been dumped in village wells and ponds by people not aware of the risks from the H5N1 virus.
Villagers are reported to be reluctant to hand over birds
Federal officials have warned that if the pace of culling does not pick up fast, the airborne virus may spread to the remaining districts and finally hit Calcutta.
One of the districts most recently affected, Hooghly, is close to Calcutta and contains the state's largest chicken hatchery.
"If this spreads to Calcutta, there will be panic and chaos," animal disease expert Barun Roy said.
The municipal authorities in Calcutta are not prepared for such a situation, he said.
Another district recently hit by the virus, Cooch Behar, is close to the border with Bangladesh.
West Bengal has sealed a stretch of its border with Bangladesh, which has been fighting to contain the spread of bird flu since March last year.
Experts in Bangladesh have warned that the outbreak of the virus is far worse than the government is reporting.
"Bird flu is now everywhere. Every day we have reports of birds dying in farms," leading Bangladeshi poultry expert MM Khan has said.
"Things are now very serious and public health is [in] danger," he said, alleging that farmers were reluctant to report new cases.
There is little evidence that the virus can be transmitted easily between humans.
Most human victims have contracted the disease through close contact with affected birds.