Foie gras is considered a luxury food product made of the liver of a duck or goose that has been specially fattened. By French law, foie gras is defined as the liver of a duck or goose fattened by force-feeding corn with a feeding tube, a process also known as gavage. In Spain and other countries, it is occasionally produced using natural feeding. Ducks are force-fed twice a day for 12.5 days and geese three times a day for around 17 days. Ducks are typically slaughtered at 100 days and geese at 112 days.