While I was checking frames, I saw a golf ball size of bees on one frame. I checked and there was the queen seemingly being attacked. I caught her in a cage. It took a while to get the workers in the cage to leave her alone and to get them out. I waited about 15 minutes and set the cage on the top bars and they seemed to act cordially toward her, so I let her out.
Have you ever had this happen before? What caused it and can it be prevented? Did I do the right thing by releasing her when I did?