The past couple of days when I have went out to look at the bees, I have noticed a worker fighting with another worker?bee (it doesn't look like a drone to me). It appears the aggressor has bitten or torn most of the wing structure off and proceeds to carry them a little ways away from the hive entrance. These wounded bees can still walk, but ultimately are doomed. So what is going on here? Are the bees that are being mutilated robbers, drones, unhealthy workers or something else? I have witnessed this maybe three times in the last three days, but otherwise the hive seems to be doing well. Any thoughts??