Your description is a little hard to understand what you are describing. You say that they are large single cells, usually drone cells are a mass of cells on the bottom corners of your brood combs. Your description of Â¼ inch also seems a little long to be drone cells. I wonder if they are sealed or open? Queen cells built for swarming purposes are usually built on the bottom of the frame more to the centre of the frame and when completely sealed resembles a peanut. Emergency cells are built in the centre of the frame(s). Would be good to hear another description.