I was checking some hives yesterday which I had requeened a couple of weeks earlier. I had killed the queens and left the hives queenless for a day. Then I removed three outside frames and introduced three frame nucs with laying queens into the middle of the top box. I found that some of the hives had killed their new queen and are queenless. I doubt that I would have had any problem earlier, but the bees are in intense robbing mode. What should I have done differently? I would rather not have to use newspaper and extra boxes if there was another method. Has anyone tried spraying the bees with light syrup? If I had waiting two weeks I could have made the introductions after I started feeding, but the nucs were getting crowded in three frames.