Hormones are used in industrial farming of cows and sheep to increase growth rate or milk production. Some hormones are natural, some are synthetic, and some (like rBGH) are genetically engineered. Like “no antibiotics,” the “no hormones” claim is regulated by the USDA. Documentation must be shown, but the USDA does not routinely test. Hormone use in pork or poultry production is prohibited by the USDA.