Afghan officials fear the deadly bird flu virus may have spread to a third province, a week after the H5N1 strain was first confirmed in the country.
Chicken is still available is some markets in Afghanistan
Two birds tested positive for the H5 strain in Kabul and in Kunar province. More tests are being conducted.
A spokesman for the Kunar governor told the BBC that villagers had reported seeing birds falling out of the sky.
The UN has urged a quick response, after two H5N1 cases were confirmed in Kabul and Nangarhar last week.
UN spokesman Adrian Edwards said speed was imperative in dealing with the flu outbreak.
"It's clearly important to see action rather than just statements on this and we look forward to see what the government is coming up with," he told Reuters news agency.
Although the government and the UN had taken a decision to begin culling birds, a government official said the process would begin only on Wednesday.
Protective suits have been supplied by the US military, but officials fear there will not be enough of them, according to the Associated Press.
Nine hundred chicken farms were closed in Jalalabad last week after the detection of the flu.
Confirming the death of chickens in Kunar Province, a spokesman for the governor, Zahidullah Zahid, told the BBC that at least 50 chickens had died in the village of Yargul outside the provincial capital, Asadabad.
Mr Zahid told the BBC that villagers were reporting seeing birds falling from the air.
It is feared that Afghanistan - with its proximity to Iran and India which have both detected outbreaks - could be especially vulnerable.
After 30 years of war, Afghanistan's health care system and administrative machinery are ill-equipped to deal with any outbreak of a large scale epidemic.
Following the detection of bird flu, the Afghan government put an immediate ban on poultry imports from neighbouring Pakistan. The UN spokesman in Afghanistan confirmed that no case of human infection had been detected in Afghanistan.
Six other samples taken from birds in the southern province of Kandahar and from Kunduz in the north had tested negative, officials said last week.
Bird flu has killed about 100 people since late 2003, most of them in Asia.
However the virus does not at present pose a large-scale threat to humans, as it cannot pass easily from one person to another.