DEAR DR. FOX: Why haven’t puppy mills been closed down after all these years of documented abuses? Baker writes:“Inhumane conditions have been exposed at commercial dog breeding facilities, aka puppy mills, as far back as the 1960s. Congress finally took action in 1970 and amended the federal Animal Welfare Act to specifically address concerns about puppy mills. “Animal welfare organizations have made great strides in closing down some of the most egregious puppy mills over the years, and have significantly increased the standards of care for the breeding dogs who are confined in puppy mills. “E-commerce also allows puppy mills to camouflage the substandard housing and the wretched living conditions of the breeding stock.