Every once in a while, I see some fighting at my entrances and some very roudy bees being drug out of my hives, It's not a frenzy, so I don't THINK it's robbing unless it's from and unknown hive as all mine are fairly new and yet pretty small and each has feed.... so I decided to color the syrup of each hive differently on the hive top feeders, to see if any of the colors end up in the wrong hive...... LOL I can't wait for my next hive inspection LOL