In most countries, eggs are stored on an unrefrigerated shelf.
Although this can be jarring to North Americans, it isn't that far out. After all, hens do not lay in refrigerators.
So why do we keep eggs cool? It is one way to fight salmonella contamination.
In the U.S., egg producers must wash eggs to remove contaminants. This process also removes a natural coating on the egg, leaving it porous. So the washed eggs must be immediately refrigerated and stay that way. A washed egg, if left at room temperature, may sweat, allowing the growth of bacteria that could enter the egg through the shell, according to eggsafety.org.
