Info on building these and the also idea comes from here:
This is how Todd, a valuable member of the WVBA. does it. These are his photos and description. Click to enlarge
I installed these on seven of my hives in the fall. I just checked and they still have loads of sugar left.
I used 10lb of sugar per board. I didn't add any pollen patties,
I also cut and press fit a piece of 1/2" insulation board into the top cover. I didn't worry about covering the hive bodies.
I feel that there are several advantages to these boards.
It is cheap insurance, as they didn't take long to build, and as Todd says above, anything left over can be mixed into syrup in the spring
Rain is a big factor here in the PNW., and the sugar absorbs moisture and the excess moisture is evacuated through the upper hole which also gives the bees a handy and close exit on suitable days. Last year I just dumped sugar on the inner cover, but I think this is easier on the bees as it is closer to the cluster and it also doesn't chill them as much when inspecting as they won't be up on the inner cover when the outer cover is removed. I can see the state of the candy board through the hole in the inner cover without removing it.
Winter inspections are quick and easy by simply lifting the cover quickly to see if there is still sugar. The state of the bees themselves can then be checked from outside the hive with the FLIR One which not only locates the cluster, but gives a pretty good idea about it's size.
This is a 6 frame swarm trap which I left alone with a swarm in it to see if it would over winter. It was nearing fall & I didn't want them to have to rebuild comb, so I left them alone as an experiment. It was time to change the camera cards in a couple of game cams & I thought I would justify the FLIR ONE purchase & use it to check out the trap.
Much to my surprise it is full of bees! The display has a range of color combinations I can use. This one shows the entire box hot with the main cluster on the right 1/2 which is normal, as that is where the entrance is. They were flying in & out.