I combined a swarm and a queenless nuc last weekend. I have seen the queen several times in the swarm. Have had them for several weeks. I also had a nuc that was queenless. I decided to combine them last Saturday. I checked on them yesterday. There was some capped brood, larva, but I also saw 2 queen cells being pulled. They were not capped yet and they were in the middle of a frame. I am thinking they may be replacing the queen. I will monitor to see if they finish capping them. Not near crowded enough to swarm. I guess you never know the age of the queen in a swarm. Think I am on the right track in my thinking?