It can be a good idea to remove brood frames that have been in the hive for a long time and replace them with fresh frames. This can also reduce the pathogen load in the hive and alleviate the chance of swarming in the spring.
The comb in brood frames gradually becomes darker over time as the wax hardens and the brood cells are reused multiple times. The brood cells shrink in size and can be blocked with propolis. Replace the old frames with new empty ones and the bees will build fresh comb. When doing a brood inspection, look out for dark, hard comb - these are the frames you want to replace.
If there is no brood in the frame you want to swap out, you can immediately remove it from the hive. Check for the queen and shake any bees off the frame and back into the hive. If you’re using foundationless frames, you can simply cut the old comb out with a knife or hive tool and replace the empty frame. If you’re using foundation, you’ll need to have new frames ready to replace the ones you remove.
Don’t remove brood or eggs
If the frame you want to replace contains brood or eggs, you’ll need to wait until they’ve hatched before removing it. Take the frame out of the brood box, shake the nurse bees back in and put the new frame into the super. You can temporarily remove one of the Flow Frames to make room for it. Put a new frame into the brood box and make sure to put the queen excluder on top of the brood box. Another option is to move the old frame from the centre to the edge of the brood box. Bees usually store honey in the edge frames.
You can remove the frame once the brood has hatched. This can take up to 3 weeks if there are eggs in the frame. Capped brood will hatch within 1-2 weeks.