I’ve been experimenting with drilling holes in my foundation so my bees can move from one frame of honey to the next in the winter without breaking cluster.
The bees reduce the hole to the size of bee space. It some cases they seem to fill in the hole altogether. They seem to keep it open closer to the brood nest, though it’s difficult to judge that this early in the game. I suppose the bees can open and close the holes as needed. But whatever is going on, it doesn’t seem to bother the bees and I imagine it helps them move between frames in the winter.
It’s possible the holes could create an unwanted draft in the winter, which means this modification to the foundation would do more harm than good. But I’ve been doing it for four or five years now and so far so good. None of my colonies have starved to death over the winter by not being able to move between frames of honey.