Those aren’t my videos:
In my humble opinion, the hives in the video are undersized. I use three brood boxes minimum and most of my hives have gone to unlimited brood nests, allowing the bees to expand as nature intends. For instance, some of my hives wintered with three deeps and 2 mediums for the last couple of years.
Please don’t read too much into this method though; having 50 hives affords me the opportunity to see what works best.
With three deeps, the bees use the bottom box for pollen storage and brood on the center two frames: The middle box is usually wall to wall brood with honey and drones on the outside: The top box is mostly honey with brood in the center.
These hives rear brood all winter long here in the NE USA and allow drones to winter over. They come out of winter much farther ahead of my smaller hives.
One of my hives on February 8th
https://photos.app.goo.gl/nw4yeoqDFyrNo98x1