Firts, are they swarming? Forum is wrong placeto ask that. Only right way is look the brood box.
You have 3 boxes and one box has capped honey.
It is surely tight inside. If bees make one capped box, they need 2 other boxes where they rippen the honey. bees must slow down working if they have not proper place where to put honey.
Brood needs 2 boxes. They store pollen near brood.
It seems that you ogt to put 2-3 boxes more to the hives.
- Give foundations. They draw combs well in good flow.
- look queen cells. If they have queen cells, make at once false swarms.
- move all honey frame up and put in lower box foundations.
- put allways exctracted box and foundationds between honey and brood.