Newton Abbot Beekeepers

The Queen has a much longer abdomen than workers, only she is able to properly reach the bottom of the cell to lay her eggs. Usually laying workers will lay in a random brood pattern, sometimes multiple eggs and often on the sides of cells rather than the bottom. Because they are unmated they will always lay drones, usually these are smaller than drones produced by the Queen.

There are other reasons for multiple eggs however, which do not mean laying workers. If the Queen has just come into lay, often the space  for her to lay has become limited by honey/pollen filling the brood chamber. Multiple eggs in a cell can be simply a case of too little space in the brood chamber for her to lay. This is especially a problem when there is a lot of nectar coming in, so space in the supers as well is important. If there is not enough space the Queens laying rate is restricted and the brood pheromone remains low, this may promt the workers to perceive the Queen is failing and stimulate them to produce Queen Cells.

A lot of people leave more than one Queen Cell (an heir and a spare) to hatch. When a colony is large, more than one Queen may be allowed to hatch. In this case the colony may produce a Cast (a secondry swarm with a virgin queen), but the virgin Queen or a newly mated Queen is often able to get through the Queen excluder and she may be chased up by a second Queen or the workers. In this case you may find yourself with an extra Queen in your supers. Alternatively, if there is restricted room in the brood chamber for her to lay, before she reaches her full size, she may nip up into the supers to lay.