If you capture a swarm and put an excluder between the bottom board and brood box. How long do usually leave the excluder? With me, it's usually 3-4 days.
i havent ever used the excluder so my answer is zero days. I reduce the entrance and try to put a frame of drawn comb in with them when i hive them.
Yes, if the queen is a virgin she will not be able to mate and the bees will eventually turn on her and kill her with no way to replace her. Drones won't be able to take cleansing flights or get out to mate with the queen if she needs it. I'm sure there are other problems that I'm forgetting.