Take a frame of open brood from your strong colony and gently brush the bees of it so you don't accidentally transfer the queen and put it in the weak hive. Do it again the next week and check the first frame and if you are queenless, you should have structures that look like peanuts. Those are queen cells and you have time to raise a queen. Just stay out for three weeks after you see the cells. That does not mean you should not check to see if the bees need another box. Bees with no brood can store a lot of honey. Adding a third frame of brood with no bees next to the cluster in the third week would be a good thing to do to to keep the colony population up. If you just take a frame of eggs and no bees you aren't impacting the other colony much at all. The queen can lay far more eggs that the bees can care for.
I am checking the hives every 7 days. Just a quick inspection - taking out the outermost frames and looking for brood, honey etc. I have 2 hives. One is rocking and has built up 8 out of the 10 frames. Full of capped brood and honey. A week ago other one had started to build out the foundation on one of "my" frames (not an original nuc frame), but when I checked it this week there hasn't been any more work on that frame or any of the other frames aside from the 5 original nuc frames. Additionally the hive doesn't seem to have great numbers. Compared to the other hive it is 1/2 (or less) the size. Does that make sense?
