Farm fresh-egg shells are thicker and harder than store bought egg shells developed in factories.
Just like our own bodies, chickens and ducks need to be treated well to produce the very best. Wellness and happiness are proven factors that make eggs taste better and hold more nutritional value than store bought eggs. Eggs should never come from animals under stress. 
Farm-fresh eggs also have a protective shell seal, straight from nature, that allows them to be kept at room temprature. Per the FDA all store bought eggs are treated chemically to have this protective layer removed, thus store bought eggs must be refrigerated.