I lost one hive out of 13 over the winter. In fact, I lost it mid to late February… AFTER I put a candy board on it. This hive came out of the winter nice and strong. It was one of my larger colonies. They were bumping the lid after going through a full medium of honey. So, I added on a candy board just for some food before were out of the cold. To be clear, I’m an advocate of candy boards and will continue to use them for all their benefits. Below is a recent negative experience based on my specific application and circumstance.
I was in this colony about three times prior to the deadout. I put a little piece of pollen patty in on a previous visit (I start with a little and see if they take it) and there were a LOT of bees up in the candy board. I came back about a week later and they were all dead. They were loaded in the candy board, on each deep level and even a carpet of bees on the bottom board. It looked like they had been poisoned. Yet, the 4 other hives next to it were fine.
I did my mite wash and it was fine. No mites in the wash! There was plenty to eat in the candy board. So, I sent off a bee sample to the Beltsville lab for good measure. See the report below. It’s exactly what I expected. Very low mites and no nosema. So yeah, a nice clean hive otherwise!
This is the one and only candy board that I used 1/4″ hardware cloth on. I have used this same board for 3 past winters with no issue. However, this particular colony was very strong. It had a ton of bees that ate a softball sized hole up through the center of the candy. The bees flowed up and over the top of the rest of the candy totally covering the sugar. It appeared to be a carpet of dead bees when I pulled off the lid. I couldn’t see any sugar… just a tray of dead bees.
I believe that the majority of the bees were up there and on the next cold night, they couldn’t get back down through the hardware cloth fast enough… essentially keeping them from clustering and staying warm. That night, there were bees stuck up top, and not enough bees back down around the brood. Look at the captions on the following pictures as I try to indicate the play by play.
Bee diagnosis shows a clean hive. 
Newspaper added to show how the candy was in the board. The board was not full to the top so bees could come up and spread out across entire top. 
Here is the candy board with 1/4″ cloth. A single bee can get through the cloth, but with a mass up top, they couldn’t get through fast enough. 
This board, while not the same one, shows the hole they can eat up through the center. 
This board shows the proper 1/2″ hardware cloth. Bees can easily get up and down through this, even with a lot of bees upstairs.
So, as you can see, this was beekeeper error. What’s even sadder is that I added this candy board to the colony about 1-2 weeks before it caused their death. I didn’t notice this until I got the board home and emptied off the bees to see the sugar remaining. I thought they had completely consumed the sugar in the board and it was just all bees. In reality, the small hole through the center of the sugar (along with the 1/4″ hardware cloth) acted as a choke they couldn’t pass through fast enough in time to cluster.
Lesson learned. I’ll be replacing this with the 1/2″ and I hope this helps anyone else who may be using something similar.
so why not doing 1/8 wire, that way they would just stay on bottom, and eat the sugar from there, without going up! i am going to do the candy boards but i was thinking in 1/8, but i see all of it in 1/2 , why bees cant stay on bottom and get it from there? please let me know your thoughts on this, as i am making them now for winter. Toronto
They have to be able to get up through because it’s hardened sugar that will not always fall to the screen. They’d be able to eat a little, then it would just be too far up for them to get through #8. Sorry for the delay in response.