Jen , it was my fault. Back in mid Oct. bee's were sucking down 2:1 sugar water. I found that I had a problem with a Aug. swarm, so I put all effort in that hive to get it nuced down, when weather allowed, and should have looked in other hives during that time. Lesson learned, did sugar roll on that hive in late Aug. 2 mites. I assumed hive was healthy as bee's were bringing in pollen and sucking up sugar water, just like other hives. Lesson never assume. I had a weather window to install shims and cakes 2 weeks ago, that's when I seen , there was a problem. Nuc-ed it down to bottom 10 deep to 6 frames with foam and follower board and couldn't find marked Q, and didn't see new Q.