For most Americans, the idea of eggs being stored at room temperature seems strange. But, the fact of the matter is that in most parts of the world, eggs are not found in the refrigerator section of the grocery store. They are simply stored on shelves and not refrigerated. The reason why is simple: Happy, healthy chickens keep their nests pretty clean and the eggs themselves have a natural anti-bacterial layer to them which preserves them naturally. A good, healthy egg can sit on the counter at room temperature for up to 6 weeks without going bad. The American agricultural system pretty much ruins all of that natural protection for eggs.
First and foremost, the majority of commercial egg factories are filthy places. The eggs they collect from them, therefore, end up being contaminated with feces and other contaminants. As a result, USDA requires eggs to be washed before being sold and the washing destroys any natural protection the eggs had when they were laid, creating the need for refrigeration. In short: the fact that eggs in the USA require refrigeration is a symptom of our broken food system. It makes us that much more happy to have our own home-raised eggs.