Roosters do not lay eggs and do not grow as large as chickens.
Instead, they are usually killed shortly after hatching, usually by grinding or gassing with carbon dioxide.
But from next year, France will ban the slaughter, says Minister of Agriculture Julien Denormandie.
The roosters should be thinned already at the egg stage.
- From 1 January 2022, all chicken hatcheries must have installed or ordered machines that allow them to determine the sex of the chicken in the egg, says Denormandie.
According to the Minister of Agriculture, the ban will result in 50 million fewer roosters killed each year.
"Expensive and impractical"
Breeders have long argued that sexing before hatching is expensive and impractical, but those arguments have weakened as technology has been refined.
The French state will provide targeted development aid of ten million euros to the breeders.
According to the Ministry of Agriculture, the change is also expected to lead to an increase in the average price of a carton of six eggs by one euro cent.
The French ban comes after years of pressure from animal rights activists.
Germany made the same decision in January, which will also enter into force in 2022.