Possibly queenless hive
I'm thinking that my hive may be queenless. I treated my hive with Formic Pro on October 10th, I saw capped brood and larvae on this day.
I got in there for a full inspection after 14 days (October 24th) and found no eggs, larvae or capped brood. I thought maybe the queen didn't lay during the treatment. So I checked again today and there's no sign of a queen and the bees were pretty aggressive.
Will the hive make it through winter without a queen?
Is it possible that she's hiding and hasn't been laying for the last few weeks?
Is it possible to requeen at this time or is it too late?
When the weather is so cold, it's normal that many colonies would not have any brood. Races like Carniolan (or any cold hardy race) will completely shut down brood.
When temperatures get this low, we cannot inspect the hives anymore and we cannot introduce new queens either.
In previous seasons we heard from beekeepers that thought they were queenless, just to find the colony alive and with brood in March of the following year (you can ask Pat from the BBA about this since it happened to her too).
At this point of the season in the Inland Northwest, we recommend to shut down and close up the hives.
The only activity we recommend to do over winter is removing dead bees off the bottom board, about once a month (to keep the bottom entrance open).