French authorities started slaughtering ducks in the main foie gras-producing region on Thursday to try to contain a dangerous form of bird flu.
Operations to destroy birds got underway in three departments of southwestern France where an outbreak of the H5N8 virus hasn't stabilized.
The virus, which is particularly aggressive in poultry farms, doesn't transmit via food and is harmless to humans.
The French Agriculture Ministry said in a statement that all free-range ducks in a zone covering parts of the Gers, Landes and Hautes Pyrenees departments will be culled. Poultry and ducks grown in confined spaces won't be destroyed, while farms that don't sell live animals and where birds are grown from ducklings to the final products won't be affected by the measure.
The cull is expected to last until Jan. 20 and could potentially affect as many as 1 million ducks.
Since December last year, 89 outbreaks of bird flu have been reported in France, most of them in southwestern France.
According to the French foie gras producers federation, the previous bird flu outbreak in December 2015 resulted in a drop of 25 percent in the production of foie gras after about 300,000 ducks were destroyed.
The agriculture ministry said the current quick spread of the virus justified the cull, which will be accompanied by compensation measures for farmers.
Farmers' union Confederation Paysanne welcomed the decision not to kill birds raised on a single site, and urged authorities to think about a reshuffle of the whole industry in order to limit the transportation of animals.
"One needs to stop turning a blind eye on this ultra-segmented industry where gigantic structures use transportation to excess, over hundreds and even thousands of kilometers," the union said in a statement. "This is the industrialized production that causes and amplifies sanitary crises."
The H5N8 strain of bird flu also has hit neighboring Germany. On Thursday, the zoo in the northeast German city of Schwerin was closed after the virus was found in a snow goose. The zoo also said it would have to kill geese and ducks that live in the grounds as a precaution. Other zoo birds such as pelicans and storks were brought indoors.
It wasn't clear when the zoo would reopen.