There wasn't a huge drone population.
Compared to my test colonies which have a whole frame available for drone production, this colony had far fewer
Edit: I'm sorry. I think I misunderstood what you were saying. Do you mean my test colonies or this ladies colony?
My test colonies which show no real interest in swarming still have plenty of drones (Year 1 and 2), but this may be because I gave them a drone comb. This ladies colony had fewer drones than the test colonies even though it swarmed.
I see what you are saying though: a colony which is attempting to reproduce would want to get its genes out there. Are you saying that they would increase their drone production at the same time as making queen cells? I have never noticed this (although a queenless colony or one with a virgin will support more drones).