The Suffolk farm at the centre of the bird flu outbreak is resuming the slaughtering and processing of turkeys.
Live birds are being taken back in to the Suffolk farm
Some 159,000 turkeys were culled after the H5N1 strain was found at a Bernard Matthews plant in Holton on 3 February.
The government has now given it the go-ahead to restart operations and poultry have begun to arrive there.
They are being taken in under a special licence that allows them to cross into the exclusion zone which remains in place around the site.
The first consignment arrived at the plant early on Tuesday, just hours after the government had approved the resumption of operations.
A spokeswoman for the company said turkeys were arriving from more than 50 Bernard Matthews farms around Britain, which were not affected by the exclusion zone in Suffolk.
She said: "These turkeys will be going into processing, and all of this processing and movement that is going ahead has been approved and cleared by Defra, the State Veterinary Service and the Meat Hygiene Service."
A Department of Environment, Food and Rural Affairs (Defra) statement said birds would enter into the protection zone from an area that was "currently free of disease and are due to be slaughtered as soon as they arrive at the slaughterhouse".
"They will not come into contact with other birds or meat from the protection zone," said the spokesman.
Environment Secretary David Miliband said the plant's slaughterhouse had been re-licensed by the Meat Hygiene Service after cleansing and disinfection at the site, and the Food Standards Agency (FSA) had investigated all aspects of the slaughterhouse and found them "of an appropriate standard".
1 Feb: Vets called to Bernard Matthews farm in Suffolk after turkeys die
3 Feb: Vets confirm H5N1 strain and turkey cull is begun
5 Feb: Environment minister says most likely cause is from wild bird, but other possibilities being investigated
6 Feb: Cull of 159,000 turkeys completed at the farm
8 Feb: Government vet suggests turkey meat from Hungary may be to blame. Bernard Matthews denies link
9 Feb: FSA examines whether infected meat may have entered food chain
10 Feb: Supermarkets deny there has been a slump in poultry sales
12 Feb: Slaughter and processing of turkeys to be resumed at plant, it is announced
Dame Deirdre Hutton, of the FSA, said nothing had yet been found to suggest a risk to public health, although she did admit that it was a "possibility" that infected poultry had entered the food chain.
Officials are still trying to work out where the H5N1 virus found in the farm came from - there have been suggestions that it could have come from a wild bird or from infected poultry from Hungary.
The H5N1 strain was found on a Hungarian goose farm in January, and UK officials said later that the Suffolk strain "may well be identical".
Bernard Matthews has a processing plant in Sarvar in Hungary, about 160 miles away from the goose farm.
'Clear and open'
Meanwhile, Liberal Democrat environment spokesman Chris Huhne has suggested Bernard Matthews had not been "absolutely open" with the government about the bird flu outbreak at its Suffolk site.
But in a statement, Bernard Matthews said: "Bernard Matthews has never withheld any information and will continue to assist Defra with its ongoing investigation."
European Commission health spokesman Philip Todd told BBC Radio 4's Today programme that "there is no conclusive evidence to show that the virus has reached England by means of meat being exported from Hungary to the UK".
A meeting at the commission's headquarters had earlier heard that records dating from November show no turkeys from the affected Szentes region in Hungary were transported to the Matthews plant in Sarvar.
Mr Todd said: "The evidence suggests that there is a strong correlation between the two viruses. But what we don't know is, if it is the same virus, how it got from Hungary to the UK."
When asked if Bernard Matthews had been "completely open" with the authorities, he said: "I think there are certainly some questions about the levels of co-operation or the speed of co-operation that there has been between the company and the UK authorities."
European Union officials have said they expect results by Tuesday of tests into whether the two strains were directly linked.
The H5N1 virus, which causes bird flu, does not pose a large-scale threat to humans at present as it cannot pass easily from one person to another.