Britain has ordered 2m doses of avian flu vaccine for captive rare and endangered birds but the treatments may take two months to arrive, the environment department said last night.

Zoos in the UK, which have been pressing for standby stocks, greeted the news with relief. Some zoos in Europe have begun vaccinating already, and yesterday the European commission gave France and the Netherlands permission to start poultry immunisation schemes.

Last night Austria said two chickens and three ducks had the deadly H5N1 virus, the first time it had appeared in poultry rather than in wild birds in the EU. However, those birds were suspected of having been kept with an infected swan in a sanctuary at Graz. Seven EU countries have reported the virus in wild birds.

The British move will encourage campaigners for free-range flocks here to press the government for further emergency vaccine supplies. They believe officials are putting them at a disadvantage compared with industrial battery producers who see vaccination as a last resort.

Defra said: "Such vaccines ... would be held in reserve ... as a conservation measure for rare and endangered species."

Patrick Holden, head of the Soil Association, said this was "a crack in the door". Mass culling in a disease outbreak, such as happened with foot and mouth, would be "medieval and barbaric".