New York City has become the latest place in the US to ban the sale of foie gras, prompting the country’s largest producer of foie gras to vow to mount a court battle to overturn it. Foie gras, French for "fat liver," is made from the enlarged livers of force-fed ducks and geese. Animal rights groups say the force-feeding process is painful and cruel. Poultry farmers say their practices are humane. The largest US maker of foie gras, Hudson Valley Foie Gras, in Ferndale, New York, said New York City represents about a third of the farm’s revenues and rather than planning to adjust its business, manager Marcus Henley intends to go to court to try to overturn it.