I don't think the bullying analogy ["In Defense of Foie Gras," Letters, July 6] is relevant, because humans can be too conflicted to always make the simple, sensible choice. Note the stories about battered significant others who return to their tormentors, sometimes at the cost of their lives. Even if all the fowl facts were true, it still doesn't justify the production of foie gras. There's a crucial difference between spontaneous "hyperphagia" and foie gras feedings: who makes the choice to overeat. Since the birds are obviously capable of overeating with their own beaks, having a tube stuck down their throat and food poured down it is clearly not their choice.
Many birds and mammals include "hyperphagia" as part of their normal annual cycle of life. Sometimes it's an adaptation to the common "feast or famine" availability of fresh food. Sometimes it's done at particular phases of the migration cycle. Humans are adapted to the feast-or-famine cycle, because it's only relatively recently that we got really good at food preservation (no, agriculture is not required). Our obesity epidemic started when we got rid of the famine part.
Since ducks and geese are prey to some other birds, and a number of mammals, etc, they don't get "left to their own devices" very long at one time in a natural ecosystem. It's hard to pig out when some other critter is trying to catch and eat you. Like many humans in our sedentary, sheltered society, they haven't adapted to it.
Unlike some foie gras opponents, I'm a die-hard omnivore, not a vegetarian. But I'm also an opponent of domestication of plants and animals, and the choice thing is part of it. Denial of choice to another creature is a type of mental cruelty.