It is a well known fact that the best flavoured eggs and ones that last the longest are those that are the freshest. There is actually a tip to pick the freshest ones of the lot when you visit your nearby grocery store. The basic idea is to inspect the three-digit code on the carton itself rather than judging the eggs by their sell-by date.
Food52 explains this in further detail. Since the sell-by date printed on the carton can only be up to 45 days following the date of packing, there is a very convenient method to test its freshness. There is a printed code on the side of each carton of eggs. The last three digits are referred to as the Julian date. Numbers starting from 001 to 365 denote the days of the year which clearly indicates when they were packaged. Simply pick the ones with the highest number since those will be closer to the current date.
And voila! Who had any clue that picking eggs would be so simple; yet, a technical endeavour to spot the freshest ones of the lot. Food52 has many other guides that can help you out, for instance makign yourself the perfect egg sandwich.