The production of pâté de foie gras involves force-feeding ducks and geese by placing a long tube down the birds’ esophagi and pumping an unnatural quantity of food directly into their stomachs. Force-feeding induces hepatic lipidosis and causes the birds’ livers to become diseased and enlarged. Substantial scientific evidence suggests that force-feeding can cause pain and injury from feeding tube insertion, fear and stress during capture and handling, gait abnormality due to distended livers, pathologies in liver function, and increased mortality. Force-feeding birds to produce foie gras is detrimental to their welfare.
The Humane Society of the United States, "An HSUS Report: The Welfare of Animals in the Foie Gras Industry" (2012). IIA. 22.