While observing my three hives in the back yard, I noticed that the first hive had a few grey honey bees going in. I have never seen that light of a bee. Any guesses ? The hive seems strong I doubt if they are robbers from a different hive.
Possible newborn bee or a bee with deformed wing virus. Check this out. It was a photo from my hive a while back.
http://www.midstatebeekeepers.com/hive_photos/sick_bee.JPG
Don't panic, the queen mates with as many as a dozen or even more drones during her maiden flights. She could be carrying sperm from several different varieties of bees: Italian, Carnoilans, Russian, and Buckfast, to name a few.
Another possiblity is that those bees got there from drift from another hive or got tired from carrying a heavy load and stopped off at the closest hive to unload, in which case you are now a little more nectar and a few bees richer. (that last sentence sounds rediculous, but believe me it happens.)
Looks like a newborn to me.