How to control humidity in an incubator
Humidity and temperature are the two most important factors when it comes to hatching eggs in an incubator. Temperature can be controlled relatively straightforward, but humidity can be a bit more tricky. In this article I’ll show you how to control humidity in an incubator by telling you:
- Why humidity in an incubator is important
- What the humidity in an incubator should be
- How you can adjust the level of humidity in an incubator
- Some general tips and tricks
- Where to place your incubator
In case you are short on time I would like to mention that nowadays there are great incubators on the market that include fully automatic humidity control. If you want to see a few, check out my best egg incubators article. If you do have the time, not buying automatic incubators and instead doing everything the old fashioned way definitely has its charm!
Why is humidity in an incubator important
When an egg is initially laid, the egg is full of various liquids, including some moisture. During the incubation process, the egg will slowly lose some of its moisture through the pores of the shell. The amount of moisture the egg loses depends on the outside humidity. When the egg loses some of its moisture an air cell will form inside the egg. That air cell is where the chick decides to hatch. If the air cell is too small, the chick might drown while pipping through the shell. If the air cell is too large, the membrane might end up being too small for the chick before the pipping process begins. When the size of the air cell is exactly right when the pipping process begins, the eggs have the biggest chance to hatch successfully.
What should the humidity in an incubator be
Here is where it gets tricky. Unlike as with temperature, there is no perfect answer for the optimal humidity level in an incubator. It always depends on the embryo growth. There are however two important aspects. First off, the air cell should be about 13-14% of the total volume of the egg when the pipping process begins. Secondly, during the lockdown period the humidity should be a lot higher than before. Somewhere in the 55-75% range.
When it comes to the three weeks before the lockdown period, some chicken hatchers prefer to keep the humidity very low. Possibly as low as 25% (dry hatching). While others keep the humidity above 50% right from day one. Personally I’m more a fan of lower humidity levels during the first three weeks, but it is important to try out what works for you.
What you should do is candle the eggs every week to check on the development of the embryo and the air cell. After the first week the air cell should be about 4%, after the second about 9% and after the third about 13-14% of the total volume of the egg. If the air cells are too small you will need to lower the humidity. If the air cells are too big, you will need to raise the humidity a bit. Depending on how much too small or too big the air cells are, you should adjust the humidity by 5-15%.
How to adjust the level of humidity in an incubator
How to increase humidity in an incubator
The best way to get the humidity up in an incubator is to put more water in the incubator. If that isn’t enough, try to keep the incubator closed as much as possible. Every time you open the incubator some of the humid air gets out and is replaced by not so humid air. If neither of those are enough, you can add an extra petri dish of water somewhere in the incubator. This will result in more water evaporating, which increases the humidity a lot.
How to decrease humidity in an incubator
The easiest way to decrease humidity in an incubator is to simply open the air vents and remove water from the incubator. This is in almost all cases more than enough. If you live somewhere with a very humid climate, it is possible that the outside air is too humid as well. In that case you can either buy a dehumidifier for the room in which the incubator is, or add some dehumidifying objects into the incubator itself. Both rice and paper towels work great for lowering the humidity in an incubator.
General tips and tricks
- If your incubator has a too high level of humidity with the water reservoir filled, but too low when it is empty you might be able to replace the water reservoir with an ice block tray. In an ice block tray you can fill as many of the individual holders with water as is necessary for the perfect level of humidity.
- If you don’t want to check on the humidity all the time, some incubators have fully automated humidity control systems available, such as the Brinsea Octagon 20 (Amazon link). If you want to read a review, read my Brinsea Octagon 20 review.
- Don’t open the incubator during the actual hatching process in the last 1-2 days. This is because the humidity level may drop too far down, and humidity takes a lot longer than temperature to go up again.
- Try out different levels of humidity during the incubation process. There are some subtle differences between different areas and different chicken breeds, so trial and error can help you find the perfect balance for your chickens.
Where to place your incubator
If you are still having trouble with the humidity in your incubator, consider placing the incubator elsewhere. Generally speaking the incubator is best placed inside your house, somewhere without large temperature fluctuations. So not next to the heating. In some climates it can actually be better to keep the incubator outside, especially if you have a good chicken coop. In nature everything happens outside as well of course. If you want to keep your incubator outside, or if you want to let your chickens hatch the eggs themselves, make sure you have a good chicken coop. A good chicken coop should be well isolated, and have plenty of space for brooding, hatching, and the chickens to stay in at night. Some examples of good chicken coops can be found in our best chicken coops article.