FAQs at The Incubator Shop

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Humidity Questions

What's the correct humidity for hatching chickens?

Incubator humidity is one of the most discussed subjects in incubation and chicken keeping. It's open to a great deal of debate, resulting in many anxious nights for first timers and experienced breeders alike.

The first rule of incubation humidity: Don’t panic!

Unlike temperature - which needs to be kept constant - humidity can vary greatly without having any adverse effect on your hatch. Guidelines suggest an average humidity level of 50-55%. But in reality, keeping within such a tight range is almost impossible, even for incubators with full humidity control (such as the Rcom King Suro Max 20, below). Your actual humidity levels are likely to vary, up and down - between 40% up to around 65%, before heading back down again. This is perfectly normal and nothing to be concerned about.

Aim for 52% Relative Humidity. But remember:  this is only a target, not a steadfast rule. If your incubator is set to a humidity level of 55%, while the actual humidity levels will fluctuate, it will average at the set level.

My humidity will not go high enough. Why?

There are a few reasons why you may not be achieving higher humidity levels in your incubator, but there are ways you can help your incubator reach those much needed higher levels.

If the incubator has manual humidity control without a humidity display, you may find this question more useful:

'How do I monitor the humidity in an incubator which does not have a humidity read out/display'?

If the incubator has manual humidity control but does have a humidity readout/display, then the following tips may help you achieve the humidity level you desire.

  1. Ensure the incubator is in a warm room with a temperature of between 18°C-22°C.  A cold room will make it so much harder for you achieve the humidity level you want. Cold air will draw moisture out of the incubator. Make sure the room is warm and that the incubator is not exposed to wide temperature changes or a draught. This is essential to having the humidity level you need.
  2. If the incubator is not getting to the level you require, you want to double-check that the vent on the incubator is closed. If the vent is open, you are allowing that much-needed moisture in the incubator to escape.
  3. Make sure there is water in the troughs. If the instructions suggest to only fill one half or one trough the start of incubation but the humidity is not high enough add some water bit by bit to the other trough.
  4. Use humidity blocks or pads. Humidity blocks and pads are a great accessory to use if you are not getting the humidity level you want. Humidity blocks and pads increase the surface area of water in the incubator which in turn will increase the humidity. 'The Larger the surface is of water; the higher the humidity'.

 If the incubator has automatic humidity control.

  1. Check the set level. Check the humidity setting is set at the correct level you want. If the humidity is not increase it can be because the humidity setting has not been increasing to the higher level, you want.
  2. Ensure the incubator is in a warm room with a temperature of between 18°C-22c. A cold room will make it so much harder for you achieve the humidity level you want. Cold air will draw moisture out of the incubator so ensure the room is warm and the incubator is not exposed to wide room temperature changes or a draught is essential to having the humidity level you need.
  3. Make sure the vent on the incubator is closed. If the event is open, you are allowing that much needed moisture in the incubator to escape.
  4. If the incubator uses a pump, ensure the tubing is not blocked. Check for air bubbles, splits, or blockages like scale if you use tap water. Also check that the tube is in the water supply or for the Brinsea Advance pump ensure there Is water in the pump. If you have a incubator like the Rcom 20 Max, Rcom 20 Pro, Rcom 50 Max, or Rcom 50 Pro which has a built-in humidity heater ensure there is water in the incubator for it to heat up.
  5. Make sure you are using humidity blocks or pads with the incubator if has a humidity pump. The pump will drop water onto the pad which spread out, increasing the surface area of water, and therefore increasing the humidity.
  6. For incubators with pumps ensure the pump is working. If the reading is below the set level, then this could indicate an issue. Set the humidity level as high as possible to try and force a pump, look to see if the motor turns or on some incubators like the Rcom 10 Pro + and Rcom King Suro Max 20 you can test the pump by pressing and holding the + for 5 seconds. If the pump is working check the tubing and replace if necessary.

If you are still experiencing issues with getting your humidity high enough in a incubator with automatic humidity control then please contact us here. 

Help! The humidity keeps rising too high in my machine.

There are a few things which can cause the humidity in your incubator to go too high. Here a few things you can do to combat it.

If your incubator has manual humidity control without a display, you may find the question below more helpful:

'How do I monitor the humidity in a incubator which does not have a humidity read out/display'?

  1. Check the environment. If the incubator is in a room where the humidity is naturally quite high, then move the incubator to another location. Make sure it is away from bathrooms, kitchens, or the room in which you dry your laundry. 
  2. Make sure the vent on the incubator is open. If the humidity has gone above the set level, open the vent and release some moisture.
  3. Make sure there is no excess water in the incubator. Accidentally flooding the base of the incubator by overfilling the water troughs so they over-flow will cause the humidity to increase above where you want it. Ensure the base is dry and there is no water anywhere it should not be.
  4. Check the humidity blocks/pads. Ensure they are not soaking wet. If they are either remove them from the incubator and allow them to dry out or replace them with fresh dry blocks or pads. This should help to reduce your incubator's humidity level.

It is quite common for the humidity to rise too high during the Summer months. The natural humidity level and level of moisture in the air during the Summer can be extremely high in the UK compared to other times of the year - like in Spring - or in other countries. Incubators cannot dehumidify, they cannot remove moisture from inside the incubator. The incubator will not be able to reach a humidity level which is lower than the ambient level which in Summer is naturally extremely high. If you experience this, ensure the incubator is in the coolest room in the house, out of direct sunlight and again, away from rooms which naturally high humidity like kitchens and bathrooms. Some breeders will run an incubator dry during the summer months as it does not need any additional moisture and the ambient humidity level is already at their desired level.

What does it mean when we say “Relative Humidity”?

Incubator humidity is a 'moving target'. By this we mean that it depends on two factors: air temperature and air pressure.

If you imagine that the air around us is a giant sponge, you could imagine that it has a certain, critical capacity at which it is ‘full’ of evaporated water and cannot hold any more. Let’s call this state '100% humidity'. If it begins to rain, and the air loses half its moisture, it could be said to reduce to 50% humidity.

In reality, however, air is different to a sponge because hot air can hold more water than cold air. That’s why hot countries tend to feel more humid than cold countries - there is more water held in the air. So 100% humidity at 37.5°C means there is a lot more water in the air than 100% humidity at 10°C. Ever wondered why carpets get damp in a cold basement? There’s your answer. The cold air in the basement cannot hold as much water as the warm air upstairs, so the basement carpets get damp instead.

A similar principle applies with air pressure too. But unless you’re planning to place your incubator on Mount Everest, it’s not likely to concern us too much.

So, in summary, ‘relative’ humidity is exactly that... it's the amount of water that's in the air, as a percentage of the maximum amount of water that the air could hold at its current temperature. This is usually expressed as RH%.

Should I increase the humidity for Hatching?

In general terms, it's good practice to increase humidity for the hatching period (days 18-21 of incubation). A figure of 70-75% relative humidity (RH) is a good target to have in mind. Higher humidity during the final three days of chicken incubation helps to soften the egg shells, making the hatch a less tiresome experience for the hatchlings.

Most incubators don’t feature automatic humidity control, and instead, rely on having two separate channels for the water. Having two channels helps regulate the evaporation, since water can only evaporate from the surface. Twice the channels means twice the evaporating surface, resulting in a higher level of humidity when all the channels are in use. An example of this is the Rcom 10 Pro, which has a circular humidity pot in the base of the incubator. The pot is split into two, allowing you to double or halve the surface area of water for greater control of humidity levels. Similarly, the Brinsea Ovation 28 EX features two separate trays in the yellow base of the incubator. You can just fill one channel, or fill them both, depending on how much evaporation you want.

And finally…less is better!

When it comes to chicken egg incubation, the No.1 mistake made by first time breeders is too much humidity. It’s vitally important to remember that embryos need air, not just moisture. Too much humidity will effectively suffocate the embryos and not allow them to fully develop inside the shells. So, when considering whether to add more water to the incubator, follow this simple rule… If in doubt, keep water out!

How often should I top up the water in my Incubator?

In manual control incubators, there is no written rule on how often you need to top up the water in the incubator because this can vary. Filling the water trough could last 5 days or need topping up after only a single day. It all depends on the environment and the humidity level that  you're trying to achieve.

If the ambient humidity is quite low (if the air of the room is quite dry), the incubator may use more water as the ambient humidity will be lower; whereas if the air in the room feels damp or humid then the ambient humidity will already be quite high, the incubator may use less water. It should be mentioned at this point, however, that a high ambient humidity can also result in the incubator's humidity level being too high. This is why you must always ensure that your incubator is in a suitable environment

Add more water as and when needed - either when it's running low or is empty. Remember it is the surface area of water which increases the humidity. More surface area = more humidity. The depth of the water makes no difference to the humidity level if the water trough is not full to the brim with water.

Please follow the instructions as to whether you need to half fill the trough,or fill it from the start till 3 days before you are due to hatch and then ensure both halves of the trough or both water troughs have water in them and just keep them topped up throughout the final 3 days.

Normally, you are going to be looking at topping-up the water every few days, but less is more. The trough does not need to be full, adding water every day to ensure the trough is full can cause it to overflow resulting in the humidity going to high.

If the incubator has a humidity display you may see the reading, go up and down which is normal. Humidity is relative and it is perfectly fine to see peaks and troughs in your humidity readings

How do I monitor the humidity in an incubator which does not have a Humidity read-out/display?

This is easy and simply done and that is to follow the instructions on humidity.

Most manual control machines without a humidity display will have two water troughs. It’s best to add water to one trough from day 1 till 3 days before your eggs are due to hatch. Doing this will - and should - give you the correct humidity as long as the incubator is in the correct environment. A room who's temperature is in the range of 18°C-22°C will give you the required humidity level.

You do not need to add water every day, and the trough does not have to be full. You just need to ensure water is covering the surface of that trough.

For the final 3 days, add water to both troughs, ensuring there is water covering the surface of both. Humidity levels depend on the surface area of water. The larger the surface area, the higher the humidity. This is why you fill both troughs on the final 3 days. The depth of the water doesn’t matter; it’s the surface area it covers.

If you are unsure and don’t think that you're achieving the correct level of humidity, you may want to check the room temperature and also look into egg weight loss.  Weighing your eggs throughout the incubation period to measure how much moisture you are losing is the best way to monitor your humidity.

For example: if you want to be losing 10% moisture but are losing 13%, then the incubator is too dry. If, on the other hand, you are not losing enough, - again wanting to lose 10% but are losing 7% - then it is too moist in the machine.

You can also look into buying a hygrometer (a device which measures moisture levels) to place inside your incubator, but we would still advise measuring the egg weight loss. Humidity displays are relatively new and for years, we used to measure the egg weight loss and add water to the water troughs. This worked and still does to this day and a lot of breeders still practice these methods as they are successful (and reliable) ways to measure the humidity.

Why is the humidity so high when there is no water in the incubator when I first turn it on?

The reason your humidity reading is higher when you first switch on your incubator even though they may not be any water in the incubator is because the incubator is cold.

Generally, colder temperatures result in higher humidity levels and higher temperatures result in both lower humidity levels and drier air - explaining why we add water into the incubator to increase the humidity level.

As your incubator begins to warm up and reach temperature, you will see the humidity level come down and ‘settle’. There is not magic number it will arrive at once the incubator has reached temperature, it will depend on if you have added water and the ambient conditions.

If the incubator is in a cold room or a room with a draught, it is likely that  without water the humidity will go quite low, as cold air will draw the moisture out of the incubator. The incubator needs to be in a room where the temperature is at least 18°C (average room temperature). If the incubator is in a room which is at the ideal temperature, then it will settle at around 30%-40%.

Ideally, we would suggest to run the incubator without any water until it has reached temperature and the humidity has settled and then add the water bit by bit. This also gives you the chance to see how much water you need to reach the desired level.

What position should the vent be in? Open, closed or half and half?

The position of the vent is dependent on the humidity level.

If you have an incubator without a humidity reading, we would advise from day 1 till the final 3 days to leave the vent half open, or closed unless you start to see the condensation or the incubator starts to ‘fog up’. In this case, open the vent as this 'fog' can be an indication your humidity has gone too high or that the room is too cold. If - even with the vent open - the incubator is still ‘fogging up’ or there is condensation, ensure that the incubator is in a room where the temperature is between 18-22°C.

You then want to ensure the vent is closed for the final 3 days. Whilst your chicks hatch, you may notice some fogging and condensation, and this is normal. If, however, you notice excessive amounts, then half open the vent.

If you have an incubator with a humidity display, then it is easier to monitor the humidity level and the position of the vent. Again as guide, keep the vent half open from day 1 till the final 3 days.

If the humidity is reading too high for a prolonged period of time and doesn’t seem to have come down then open the vent. If it won't go high enough, close the vent and again check the location.  A cold room can not only cause condensation but also draw the moisture out of the incubator.

Then for the final 3 days ensure that the vent is closed. During hatching, the humidity will naturally increase as the chicks hatch until they fluff up and dry out. This is fine and completely normal, but again if there are excessive amounts of condensation half open the vent.

How do you incubate poultry that require a higher humidity, in a 'Manual humidity control' incubator like the Mini II or Maxi II Advance?

If you are looking to incubate eggs that require a higher humidity, than hen eggs but have a manual control incubator and are not sure what to do as the instructions are aimed toward hen eggs:

The best thing to do, is the same with the hen eggs, when you come to hatching time fill both water troughs as you would for hen eggs. If are worried that will not be high enough you can use humidity pads, ensure the incubator is in a warm room, the vent is closed or purchase a hygrometer to measure the humidity level.

We would also advise measuring the egg weight loss as an effective way to understand what level of humidity you need at hatching time.

Should I have condensation in my incubator?

It is expected that you may have some condensation in your incubator during hatching time. If there is not any it does not always mean, there is something wrong or that the incubator is not working.

In a lot of cases condensation can be bad sign and could indicate either that your humidity may be too high or that the location of the incubator is too cool or cold. Condensation when your chicks have started to hatch is normal, but if they have not yet started to hatch and you are noticing excessive amounts of condensation then it could mean the room is too cold or the humidity is too high and would suggest opening the vent and checking the room temperature. Ideally your incubation room wants to be between 18-22°C.

If you are noticing your incubator ‘fogging up’ and only a slight amount of condensation during hatching then don’t worry, this is normal. It is only when you start to see excessive amounts condensation to the point where the incubator is soaking wet that you need to open the vent and let some of that moisture out or check the temperature of the location.

I can't find the long pump connector, water pump tubing and short pump connector for my Ovation 28/56 EX Incubator.

The long pump connecter, water pump tubing and short pump connecter are already fitted. They are not packaged separately in a bag of parts. In contrary to the instructions, these parts are, in fact, already fitted under the pump cover on the top of your incubator.

Please remove the pump cover and check here first. If, however, they are not fitted, please contact us here. 

Should the humidity increase when my chicks begin to hatch?

Yes, this is perfectly normally.


As your chicks begin to hatch, they emerge from the shell wet. This extra water is increasing the surface area of moisture in the machine and as a result increases the humidity.


You can open the vent if and when it does go a little too high but as the chick dries out and ‘fluffs up’ the level will come back down.


Just remember to not panic - it is normal.

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