I'd really like to know the incidence of salmonella poisoning per capita, normalised by the number of fresh eggs sold, to compare how these policies actually affect the thing we're concerned about.
From the article, it looks like we're talking about two very different systems. Specifically, [1] refrigeration, [2] free-range versus laying houses and [2] mandatory vaccinations. You would likely need data from a range of countries to even begin to see which policies are most effective by data analysis.
