Fast-food giant McDonald’s shook up the food world last week by announcing that within two years, it will require all 14,000 of its U.S. restaurants to serve chicken that is substantially antibiotic-free. It’s a huge change, because so much of poultry raising has relied on drugs for so long. What will it mean?

The announcement is important news, further evidence of the way that consumer demand has been pushing the food industry toward meat raised without antibiotic use. Customer pressure has achieved results far faster than policy attempts to change meat production, which have been mired in political in-fighting since the 1970s. The announcement puts McDonald’s in line with smaller restaurant chains such as Chipotle, Panera and Chick-fil-A, which have all