I am new to beekeeping and visited some friends who also are rather new to the discipline. I noticed something that seems unusual and would like some feedback. What I noticed was 2 distinct bee types entering my friends hive. My suspicion is that there is some robbing going on. Both of their hives are weak. I am already thinking about some improvements and will make some suggestions to them. If my observations are correct then this might help them make some changes. I did take some photo's of the bee's, but the file is too large so I will skip that for now. Most of the bee's entering the hive seem "normal" in size and color. there are other bee's coming and going, maybe 20% that are half again bigger and have a mostly black abdomen. I think these might be Caucasian or Carniolan bees. I don't think these are drones. They are acting like worker bee's. I will clarify my knowledge to head off the perception of presumed ignorance. I am the son of an phd entomologist so there is no confusion on my part as to the observation. I am familiar with the difference between bee's, hornets, wasps etc. So one question I have is; is there this much size difference depending on the sub-species of bee? Also if we close up the hives and move them 1/4 mile and keep them shut up for 3 days or so, reduce the entrance to the hive, would this help? I may make some Miller type feeders for them so that the bee's will have something to help build comb, gain strength, and have food for the time they are closed.