The outbreak in the Brittany region, France’s first farm case this autumn, occurred near where an infected wild bird was found, the ministry said in a statement.

Several cases among wild birds have been recorded in recent days, it said, adding that the government had raised its national alert level for bird flu to moderate from negligible.

Poultry flocks in areas particularly exposed to contact with wild birds would now be confined indoors, the ministry said.

Avian influenza, commonly known as bird flu, has led to the culling of hundreds of millions of birds in the past years. It usually strikes in Europe during autumn and winter and has recently been detected on farms in countries including Germany, the Netherlands, Italy, Croatia, and Hungary.

To counter the disease, which has disrupted the supply of poultry meat and eggs and sent prices rocketing in parts of the world in recent years, France launched a vaccination campaign against bird flu in early October.

The French programme is being initially limited to ducks, which are the most vulnerable to the virus. Ducks accounted for only 8% of total French poultry output in 2022.