Potential Problems With Leaving Feeding Shim On Hive All Winter?

[Alklar20]

I'm planning on getting a shim for feeding bees during the winter either dry sugar via the mountain camp method or sugar cakes (Link: https://hillcobees.com/product/winter-feeding-shim/). It's 1 5/16" tall and has a small notch that serves as an upper entrance for the bees. I was thinking about leaving the shim on the hive all winter because the bees could use the upper entrance in case the bottom entrance got clogged by dead bees during the winter. However, I'm concerned that the empty space the shim would create would cause problems for the hive; for example, heat loss. Are my concerns valid; would there be any problems with leaving the shim on all winter?

Note: The winter setup I have planned for my hive, from the bottom up, is a screened bottom board (not sure whether I'll be closing it up with the mite tray or leaving it open), two deeps, the shim, a moisture quilt, and the outer cover. The moisture quilt I plan on using will be the one at the link I've provided below; it's 3" tall and will be filled with wood shavings.
Link: https://www.funnybugbees.com/hive-components/hive-accessories/inner-hive-covers/Beehive-Ventilation-Shim-10-Frame-quilt-box-p140236073

[Bakersdozen]

Bees keep the cluster warm, not the hive. I think you are on the right track regarding adequate ventilation to prevent condensation from dripping down on the cluster.  I would close the screened bottom boards though.  Condensation vapor will rise, not down. Here in Kansas many beekeepers, myself included, put shims on in the fall just in case we need to put on emergency feed.  I usually peak in periodically to see if the bees have reached the top bars.  If they have I put on a pre made sugar brick.  The idea is crack the lid, do what needs to be done, and close it up quickly.  I always put a popsicle stick or similar on top of the inner cover at the back to allow for condensation to escape.  I have done the mountain camp method in the past but I question whether the bees were consuming it or carrying it out the entrance.  I am not sure they can digest it either.

There has been a discussion on this forum about making sugar bricks. https://worldwidebeekeeping.com/forum/index.php?topic=6293.msg80456#msg80456  There are some great recipes here.

[Jen]

Good morning Valklar, this is the set up I've used for years. I put the lid right on top of the shim, and I keep the food right next to the hole all winter long. That way the bees stay nestled together right where the warmth of the bees are down below.

[yes2matt]

I use the Mountaincamp method: newspaper on the top bars, 1.5 inch shim w no entrance slot, 4 lb bag of dry white sugar on the newspaper, spread into a nice even layer, poke a couple holes with the hive tool, top cover. I check it maybe once or twice during the winter and sometimes add dry sugar.

I think the biggest benefit of this method is the absorption of condensed moisture. When I remove the sugar in spring, it is always a solid cake.

I have in the past waited too long to take the sugar off and had 1.5 inches of honey comb mess to clear where they filled the shim space. It's not that big of a risk/drawback, and easily avoidable.

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[rober]

i mold blocks of hard candy in baking pans. i put the blocks over the cluster & add the shim. my inner covers are notched for ventilation & upper entrance usage. i then put a 1" piece of foil faced styrofoam  over the inner cover foil side down.  i check hives on warm days throughout the winter starting in january. if the bees have eaten all the candy above the cluster i'll move what's left over the cluster. i carry candy blocks with me to replace eaten candy if needed. i've been averaging 8% winter losses.
jen-
you should put the shim under the inner cover. bees will not break the cluster to climb on top of the inner cover.