“Conservation organizations have long sought to protect pandas, polar bears and pelicans, but the welfare of farm animals has largely been left to activist animal-welfare groups like the Humane Society of the United States, which calls itself “the nation’s largest and most effective animal protection organization.” For the past 10 years, the organization has been headed by the politically savvy Wayne Pacelle, who has greatly increased its visibility and influence. Under his leadership, the society has successfully lobbied to curb what it calls the worst excesses of “factory farms,” notably the use of gestation grates to confine pigs. In an interview with Yale Environment 360 contributor Marc Gunther, Pacelle talked about how treatment of farm animals is linked to greenhouse gas emissions, why his group is promoting “meatless Mondays,” and why consumers should be willing to pay more for products from animals that are sustainably raised.”