Terry checked her parent colony and it was queenless. It was hard to tell if they had swarmed and had made a new queen. By having two colonies she had another option to fall back on. By taking a frame of eggs from the queen right colony to the queenless colony she will be able to confirm if there is a queen present or not.
Checking the frame 4 days later she saw queen cells. This confirmed there was not a queen in the hive. Had she not seen queen cells we would have to assume that a queen is in there but not laying yet.
The next post shows here combining the hives.