I had missed David Friedman's post last week on eggs and quality. The whole thing is worth reading. He points out that even though the British government doesn't require vaccination of hens against salmonella, 90 percent of egg producers have their hens vaccinated. Why? Because for their eggs to qualify for the industry-sponsored label "red lion," they must be from hens that are vaccinated. Moreover, notes the New York Times, "The country's major supermarkets buy only eggs with the lion seal."
David also notes that although the tone of the NYT piece by William Neuman is that the U.S. government should regulate, and the piece cites British experience as back-up, it isn't until about halfway through that Neuman tells you that the British government doesn't regulate either.