I have a queen, mated late summer of 2012. She is marked yellow and I strictly adhere to marking conventions, so there is no chance she's younger than 2012. Last season I designated her colony for requeening simply because it was not performing to my standards. Bees were somewhat runny and broodnest was small. Late last season, she kicked it into gear and went into winter with good stores and populations. This spring the colony is amazing. Bees are calm on the comb and slammed with brood. What would cause a queen to under-perform and then do such a dramatic turnabout? BTW, I looked for other queens and none were seen. In fact I saw an egg dripping out of the marked queen during my inspection yesterday.