The European Commission on Thursday prolonged safety measures in Belgium, Germany and the Netherlands imposed to counter an outbreak of highly contagious bird flu.
Some 31 million chickens have so far been slaughtered in the three countries to contain the disease, which started in the Netherlands but has spread across borders, said the EU executive.
The commission's Standing Committee on the Food Chain and Animal Health extended the safety measures in the Netherlands and Germany until May 30. In Belgium the restrictive measures will be limited to the northern provinces of Antwerp and Limburg from May 27.
Experts say the current outbreak of avian influenza, caused by a virus known as H7N7, is not harmful for people but that the virus could mutate, triggering a potentially dangerous influenza epidemic.
In the Netherlands, where the disease was first spotted in late February, there have been 252 outbreaks, and another six suspected cases, and 28 million birds have been culled.
Under the EU rules, no Dutch poultry, hatching eggs and fresh, unprocessed poultry manure may be exported, while there is a ban on the transport of most live poultry and hatching eggs in the country.
In Germany a single outbreak has been reported, near the Dutch border on May 9. The commission extended restrictions until the end of the month, although it said some birds can be transported under strict conditions.
In Belgium, where 3 million birds have been killed, eight outbreaks have been confirmed, with the last reported on April 28.
"It can thus be concluded that the disease has been successfully eradicated," the commission said.
The committee said it would review the safety measures on May 28.
Another strain of the bird flu crossed the species barrier in 1997, killing six people in Hong Kong and prompting a mass cull of the territory's poultry.