The Bailey Comb Change.

Bailey Eke.

It’s a good time to do a Bailey Comb Change in Scotland, and with a nectar flow on the conditions are perfect. This is the original version of my recent article published in BeeCraft magazine. I’ve used a Bailey Comb Change to change brood frames from 12″x14″ to standard Nationals, and to get rid of very old comb. This year I’ve been sucessful with Shook Swarms for getting rid of old brood combs too but I’ll tell you about that next week.

Apiary Hygiene.

The Bailey Comb Change (BCC) is an apiary hygiene strategy that enables beekeepers to remove old brood frames and combs and replace with frames of fresh foundation, or fumigated and sanitized drawn comb. The original Bailey comb change would have used drawn comb but there are variations in use today.

Dr Lesley Bailey.

The BCC was devised in the 1950’s by Dr Leslie Bailey while working in Rothamstead Experimental Station’s pathology department. Dr Bailey pioneered insect virology research and inspired other scientists to continue developing this work. At this time, little was known about the effects of viruses on honey bee colonies but Bailey debunked the commonly held belief that the Isle of Wight disease was caused by tracheal mites, Acarapis woodii. He isolated the virus most likely responsible for the loss of thousands of colonies in the early part of last century which was chronic bee paralysis virus.


Besides isolating the causative bacteria of European foulbrood, another significant piece of Bailey’s work was discovering the microsporidial fungus Nosema apis, which was the cause of nosemosis then. Today, we also have Nosema ceranae to contend with, (NB these pathogens have just been formally renamed as Vairimorpha apis and Vairimorpha ceranae1.)Not only did Bailey describe the causative organisms but he created practical ways of managing colony hygiene and gave us the Bailey Comb Change, named in his honour.

I’ve used a BCC to remove very old combs from a colony given to me by a kindly beekeeper. As part of routine apiary hygiene, I make sure that every 3 years each brood box has fresh comb as advised by The National Bee Unit. I am less likely nowadays to change two or three frames every year to achieve this because the increased use of pesticides, and increasing diseases and viruses in our colonies leads to a build-up of damaging substances in wax. I like to change all the combs in one season every three years. Larval cocoons build up over many years and could reduce the size of the cells over time, though I’m told by a scientist that this is very unlikely to affect the size of the pupae because they don’t fit tightly in their cells.

Healthy Colony Comb Change

Let’s discuss the Bailey Comb Change manipulation for a healthy colony first. When you start depends on where you live in the UK. Bear in mind the popular quiz question, “what takes six weeks to travel from Lands End to John O’ Groats?” The answer is spring as we are all too well aware of in the north of Scotland! We need to take climate change into account also, and in some years the first nectar flow may be earlier or later than in previous years. An ideal time to begin is when oilseed rape flowers start blooming, and this is often the end of April/beginning of May in Nairnshire.

The principal is to carry out these manipulations before the colony reaches its peak of expansion because comb changes reduce congestion in the brood nest, and remove pathogens creating a healthier environment, and may even delay or prevent swarming.

You will need to prepare:

  • A clean brood box with frames holding foundation
  • A rapid feeder and around 4-5 litres of sugar syrup
  • An eke (Bailey eke) with an entrance and a queen excluder


An eke is a temporary spacer between two hive body parts and the name is derived from Old English meaning an addition or increase. If the eke is placed with the entrance above the queen excluder, as you see above, it means that the foragers will not get pollen knocked off their legs over 3 weeks, and they will be less likely to use the bottom brood box for storage. The down side is drones being trapped below but you not want foragers to go down there and get re contaminated with nosema spores etc from the dirty frames.

Don’t worry about the concentration of sugar syrup because it is not an exact science; rather a moveable feast, and you will not kill your bees if the proportions of sugar to water are inexact. However, you must use white refined sugar or one of the commercially available inverted feeds. Honey bees make wax and build more comb during a nectar flow when they are running out of storge space. The sugar concentrations of the nectar vary depending upon plant species, and sugars vary between 20-60%. One kg sugar to 1.25 litres of water gives a 44% solution, but a more concentrated solution will work well also.

Day 1. Position the clean brood box with frames and foundation above the existing brood box. Place the crown board with feed hole over the new brood box and place the rapid/ contact feeder directly over the open feed hole.

 An eke deep enough to hold the feeder is positioned over it.  Because bees need warmth and calories to produce wax, I like to place another crown board above the eke with the feed holes sealed off to prevent heat loss. Replace the roof and leave for a week, unless you need to top up the feeder which you would do in the evening when foragers had stopped flying for the day. Otherwise, you might promote robbing and create another problem.

 If you have a super in place, shake the bees off the frames into the top brood box and remove the super or super frames while feeding is in progress. Return the super after feeding is finished, and place a queen excluder between the top brood box and the super.

Day 8. You will find that some of the foundation in the upper brood box has been drawn out and the queen may already have moved up onto this comb. If she hasn’t then move her up onto new comb and place the Bailey eke between the two brood boxes. Because of the queen excluder, the queen remains in the new box and the newly emerged bees from the bottom brood box will come up through the excluder to join the rest of the colony. You will have blocked off the bottom entrance on day 8, and all the flying bees will use the new entrance and not go down to store pollen in the bottom box.

Day 31. All the brood should have emerged (drones take 24 days for development from egg to emergence, but the queen may have laid an unfertilised egg on day 8 before you moved her) and you can remove the bottom brood box and old comb along with the Bailey eke. The clean brood box is placed on a clean floor now. The drones will be able to get out, and if any bees are still clinging onto the comb in the bottom box, they can be shaken off into the new brood box. The foragers now return via the bottom entrance again.

Bailey Change for a Colony with Nosema.

A colony with nosema will be stressed, but a small weak colony on three or four frames of brood with a heavy infection may not be able to withstand the further stress imposed by the comb change and so it may be appropriate to euthanize the colony. Seek advice from an experienced beekeeper or local bee inspector if uncertain.

Day I. If the bees are crushed or further stressed during this manipulation they may defecate and spread nosema spores, so, handle the frames carefully. This version of the comb change involves finding the queen and moving her, on the frame you found her on, into a sanitised brood box which contains at least two drawn combs. Ideally, use four drawn combs with a frame of foundation at each side. The frame with the queen is placed in the middle of the new brood box flanked by drawn comb. If you push in a coloured pin this frame will be easy to find later. Dummy boards are positioned at either outer side.  

The new brood box will sit above the Bailey eke and there will be a new entrance above the bottom brood box. The original entrance is blocked off immediately but the bees will have no trouble orientating to the new one.

Inspect the old bottom brood box to determine how many frames contain brood and discard the rest and place dummy boards at the edges of the brood nest. Destroy the discarded frames by preferably burning, and don’t even consider rendering down the wax and reusing the frames. Mirror the number of frames in the bottom box with the same number of clean sanitised comb in the top. E.g., if there are 7 frames of brood in the bottom, put 7 frames in the top and place dummy boards at the sides of these brood frames.

Start feeding around 4-5 litres of sugar syrup in the easiest and quickest way for a stressed colony to access, and this is usually via a contact feeder. A small stressed colony affected by nosema will have a reduced workforce and no food stores so feeding this colony a stronger 2:1 sugar solution will help them build comb and new stores more quickly.

Day 8. Remove the old frame that the queen was transferred on from the upper brood box and very carefully remove any bees from this frame. Bees generally dislike being brushed but this may be the best way to remove nurse bees that tend to stick like Velcro. Shaking bees with a nosema infection risks stimulating defecation and spore spread. This frame can be placed in the lower brood box.

You might need to add more foundation or drawn comb to the top brood box.

Day 25-30. Hopefully all the brood will have emerged from the bottom brood box and moved up, but there may still be bees clinging to the frames and you must remove them without causing stress. You could use a clearer board ensuring that it is placed correctly. If Porter /other bee escapes are used, place the clearer board so that the bees go through the escape from the bottom box to the top box but are unable to return below (the opposite position from clearing bees from honey supers). You might find brushing gently easier than using a clearer board.

At the end of this manipulation, the queen will be in the new brood box with a lower entrance. The Bailey eke, old brood box, frames and floor have been removed, and the clean brood box is sitting on a clean floor.


That the queen is placed on the frame, on which she is found, in the new clean brood box may seem contradictory when the aim is hygiene and reducing nosema spores.  The reasoning is that the colony is already very stressed and placing the queen on empty drawn comb will cause further stress. She may be isolated from the rest of the colony because there are no nurse bees in the top box yet and the other bees may return below overnight. The queen settles back to work more quickly on a familiar frame which contains nurse bees and emerging brood.

 Nosema can kill sperm so the queen may become infertile and you may need to requeen this colony when they recover.

The old proverb “There are many ways to skin a cat” is a reminder that there are often several ways to achieve the same outcome in beekeeping so don’t worry if not all “how to” articles are exactly the same. The methods I’ve described will work for you.


Thank you to Stuart Roberts, Master Beekeeper, for proof reading my work and offering advice, and to Linton Chilcott, Basic Beekeeper Certificate, for designing the diagrams.


McAfee, A. (2022) Wintering Colonies Indoors, American Bee Journal, March 2022, Pages 331-334.

5 thoughts on “The Bailey Comb Change.”

  1. A really useful article Ann. I will bring it to the attention of our Honey Bee Health certificate candidates. The diagrams are the best I’ve seen for the Bailey Comb change so a big thank you to Linton.

    Vairimorpha doesn’t trip off the tongue quite so easily as Nosema, it might take a while to make the transition.

  2. Hi, a great and timely article!
    One of my hives was diagnosed with Nosema last night and so I was planning on doing a BCC. However the hive already has 2 supers on it due to a good flow and the numbers of bees.
    I can’t find anything about what to do in this instance.
    I see you have mentioned about removing a super during feeding, but I’m worried about the amount of bees there are in the 2 supers.
    I was thinking of putting the new brood box on top of the old, then putting the supers on top of that.
    But what would I do about feeding in that case?!
    Any ideas / tips will be gratefully received!!

    1. Hello Claire,
      Are you putting any fumigated drawn foundation in the top brood box? If you can that would be good. The colony sounds strong if you have had to put 2 supers on. That you currently have a good nectar flow should mean that the bees will be able to draw out the new foundation without a feed so what you propose sounds good. Under these circumstances, they should have drawn most of the comb out in a week. You can check next week and see how it is going and if you need to feed. I hope this helps.Best wishes for success, Ann.

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