The Dutch Agriculture Ministry ordered farmers on Tuesday to keep their poultry indoors from Sept. 1 to protect flocks from the threat of avian flu from migrating birds.
"During the forthcoming migration period, there is a risk that migratory birds can spread bird flu," the ministry said in a statement.
"For this reason all holders of chickens, geese and other birds should keep them indoors."
Alternatively, farmers can construct an enclosure that would make contact with wild birds impossible, it said.
The Netherlands, Europe's second biggest poultry producer after France, reported two suspected cases of the highly pathogenic H5N1 bird flu in owls at a Rotterdam zoo earlier this month but later said initial tests ruled out the disease.
Final test results are due later this week.
The Netherlands, which is also a top world poultry exporter, has never reported H5N1, found in several other European Union countries, in commercial poultry.
Scientists have suggested that migratory birds play an important role in the spread of the H5N1 virus, which originated in Asia and has killed 141 people worldwide so far.
Earlier this month, the Netherlands found a low-pathogenic H7N7 bird flu strain at a farm. Authorities culled all the 25,000 chickens at the infected farm and temporarily sealed off another 130 farms for testing to prevent a major outbreak.
Five countries -- Russia, the Philippines, Singapore, Taiwan and Hong Kong -- banned imports of Dutch poultry and poultry products, even though Dutch authorities said all tests were negative and assured the situation was under control.
Officials have said that the detected H7N7 strain is less dangerous than the one that hit the Netherlands in 2003 and was not a threat to human health but measures were still needed as it might mutate into a more aggressive form.
The Netherlands suffered a devastating outbreak of H7N7 avian flu in 2003 that led to the culling of 30 million birds, about a third of the poultry flock.
The ministry said farmers who have vaccinated their poultry against bird flu can still keep the birds outdoors after Sept. 1.
The government launched a vaccination campaign earlier this year to reduce the risk of the disease.
But most farmers preferred not to vaccinate as they feared that importing countries would refuse to buy their meat and eggs because of consumer worries about possible health risks.
