I have three top bar beehives with solid bottom and end entrance, they are located down the road not far from my house, all three beehives have colonies I caught in my swarm traps. Last week when I visited the hives a noticed a bunch of bees flying around in circles and buzzing in front of one of the hives, Today I visited the beehives to put an entrance reducer on that particular hive(the other two already have reducers) there were only about three bees at the entrance, as soon as I my hand and entrance reducer became visible to the bees at the entrance a large number of bees started pouring out of the hive! about twenty five rushed to my head hitting my veil and buzzing aloud. I went ahead and placed the reducer at the entrance, at this point I had "tons" of bees hitting my head and torso and a bunch of bees were outside the entrance very agitated and buzzing. I backed away from the hive about forty feet with about twenty bees following me hitting my veil and buzzing the entire time, I stood still and calm for what seemed a long time and the bees continued to be aggressive, I walked back to the beehive and some more bees flew towards me. I backed away from the hive and walked over to my truck and stood there for a long time waiting for the bees to go away until I finely decided to quickly get in my truck and drove away in my bee suite. Any thoughts or suggestions from experienced beekeepers?