The FDA rejected mandating that hens be vaccinated against salmonella. In the United Kingdom:
There are no laws mandating vaccination in Britain. But it is required, along with other safety measures, if farmers want to place an industry-sponsored red lion stamp on their eggs, which shows they have met basic standards. The country’s major supermarkets buy only eggs with the lion seal, so vaccination is practiced by 90 percent of egg producers, according to Ms. Cryer.