It's funny how McDonald's -- the much-reviled little hamburger stand that grew -- has become the world's handiest barometer of social change. It is the standard-bearer, or more often the whipping boy, for economic and cultural globalization, with progress or regress thereto measured in degrees of "McDonaldization." According to economist Thomas Friedman, it is the unwitting harbinger of a new world order in international affairs. No two countries that have opened their doors to McDonald's, he says, have since gone to war with each other. And now, the burger behemoth is at the leading edge of another wave of change: the slowly evolving concept of animal rights.

Last month, the chain announced plans to improve the way U.S. poultry farmers care for their hens -- something it is well-placed to do, since it buys 1.5 billion eggs from them annually. McDonald's has told suppliers that its continued custom depends on their compliance with strict new regulations: Each caged hen must be given 50 percent more space; the withholding of food and water to enhance egg production is banned; and the practice of cutting off the overcrowded birds' beaks to stop them pecking each other to death is to be phased out.

This is not a first. The European Union has already banned nonfeeding and requires the phase-out of all cages by 2012. But it is a giant step in the United States, where the government has lagged far behind industry in following the European trend of regulating the way food animals are raised. The significance of it is that McDonald's' sheer size and high global profile has the potential of turning the trend into standard practice worldwide.