When it comes to artificial incubation, humidity is just as important as temperature. If temperature drives embryonic development, humidity mainly regulates the egg's water loss and directly influences the quality of hatching.
Many beginner breeders only focus on the degrees of the incubator and neglect this parameter. In reality, the wrong humidity can compromise the whole process even if the temperature is correct. That is why knowing the right values and knowing how to manage them at the different stages is crucial.
Another important aspect is that humidity never works alone. It always works together with temperature, ventilation, egg rotation and the stability of the external environment. Therefore, when hatching problems occur, the cause is often not a single glaring error but a combination of poorly managed parameters. In an SEO cluster content, this point is very useful because it reinforces the authoritativeness of the article and makes it clear at once that humidity is not a minor detail.
Why humidity is so important
During the days of incubation, the egg must gradually lose a certain amount of water. This process is essential because it allows the air chamber to form and creates the correct conditions for the chick to develop.
If the humidity is too high, the egg loses too little water and the chick may find it difficult to hatch. If, on the other hand, the humidity is too low, the egg dehydrates excessively and the embryo may develop poorly or fail to hatch.
This is why humidity should not be “maximum”, but simply correct. Its task is not to wet the environment more, but to accompany the entire incubation cycle in a balanced manner.
On a practical level, this concept is decisive: the aim is not to create an environment that is as humid as possible, but one that is sufficiently controlled to encourage progressive and consistent water loss. Start-ups often think that more moisture means more protection, whereas in reality an excess can be just as damaging as a deficiency.
Correct values during incubation
For chicken eggs, moderate humidity values are generally used in the early and middle stages of incubation. The most common reference is:
- Days 1-18: approx. 45-55%
- Last days of hatching: approx. 65-70%
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The logic is simple. In the first 18 days, the egg must be allowed to lose just the right amount of water. In the last few days, on the other hand, more moisture is needed to help the chick break the shell and to prevent the membranes from drying out too much.
It should also be remembered that some incubators and environmental conditions may require minor adjustments. Therefore, the values should be regarded as a very solid reference, but not as a rigid formula to be applied without observation.
Moisture in the first 18 days
The first phase of incubation requires relatively low humidity. Here the aim is to promote proper evaporation of the water contained in the egg.
A very common mistake is to keep the humidity too high from the start, thinking that it will better protect the embryo. In reality, this can hinder the proper formation of the air chamber, which is crucial in the final stage.
For this reason, it is best to remain at average values for the first 18 days, without continuous fluctuations. Again, stability counts more than continuous corrections.
In a well-crafted guide, here it is also worth emphasising an aspect of method: it is better to check the general progress of the incubator than to intervene every few hours. Incubation rewards constancy, not constant adjustment anxiety.
Moisture in the hatching phase
From day 18 onwards the situation changes. At this stage the egg rotation stops and we enter the actual hatching phase.
Here, the moisture must be increased, usually to about 65-70%. This step is crucial because it helps keep the membranes softer and makes it easier for the chick to work while trying to break the shell.
If the humidity is too low at this stage, the inner membrane can dry out and become a serious obstacle to hatching. This is one of the reasons why many hatchlings fail in the very last days.
This is also the phase in which the temptation to open the incubator often must be resisted. Each opening rapidly lowers the humidity inside and can compromise the most delicate moments of hatching.
What happens if the humidity is too high
Excessive humidity may seem like a minor problem, but it is not. If it remains too high for much of the incubation period, the egg loses less water than necessary.
This can lead to:
- Inner tube too small
- Chicks struggling to position themselves
- Sluggish or incomplete hatching
- Higher mortality risk in the final phase
In practice, too much humidity can make the environment less favourable just when the chick needs the right space and trim to be born.
What happens if the humidity is too low
Too low a humidity also creates serious problems. In this case the egg loses too much water and the embryo risks being in too dry an environment.
The consequences may be:
- Excessive dehydration of the egg
- Membranes too dry
- Irregular development
- Weak chicks or chicks unable to come out of their shells
This is why it is important to avoid both excess and defect. The ideal humidity is always a question of balance.
How to regulate humidity in the incubator
Increasing or decreasing the humidity is usually done by adjusting the amount of water in the internal trays and the ventilation of the incubator. Some models make this adjustment very easy, others require more manual attention.
In practice:
- To increase humidity, water is added or the evaporating surface is increased.
- Reducing it is done by limiting water or encouraging more drying in the environment.
- In automatic models, you check the parameters on the display and verify that they are indeed stable.
It is always useful to check the manual of your incubator, as each machine has a different answer.
The importance of stability
As with temperature, stability is also very important for humidity. Constantly correcting, opening the incubator too often or moving it to unsuitable rooms almost always leads to unnecessary fluctuations.
The most delicate phase is the final one. In the last few days, one must avoid opening the machine for no reason, because one risks letting the humidity drop rapidly at the most sensitive time.
Many hatching problems do not depend on a theoretically wrong value, but on a parameter that rises and falls too often.
Most common errors
The most frequent errors in moisture management are:
- Keeping humidity too high throughout incubation
- Do not increase it in the last few days
- Open the incubator frequently during hatching
- Do not check the actual moisture tightness
- Neglecting the relationship between humidity and ventilation
- Thinking that more humidity always means more security
In reality, good hatching always stems from a balance between parameters, not from overprotection.
FAQ
What is the right humidity in the incubator?
Typically, a humidity of about 45-55% in the first 18 days and 65-70% in the final hatching phase is used.
When should the humidity be increased?
Usually from day 18, when the egg rotation stops and the final phase begins.
What happens if the humidity is too high?
The egg loses little water, the inner tube may remain too small and hatching may become more difficult.
What happens if the humidity is too low?
The egg risks becoming too dehydrated and the membranes may become excessively dry.
Does humidity matter as much as temperature?
Yes, because it directly affects the egg's water loss and hatching quality.