Incubating chicken eggs requires providing just the right environment for healthy chicks to develop One of the most important factors is maintaining proper humidity levels throughout the 21-day incubation period. This guide will explain everything you need to know about humidity for hatching happy, healthy chicks
What is Humidity and Why It Matters
Humidity refers to the amount of moisture in the air. For chicken eggs, some humidity is essential but too much or too little can cause problems. As the embryo develops, the contents shrink and an air pocket forms inside the egg. The correct humidity allows the right amount of moisture to escape through the shell as the air pocket enlarges.
Too low humidity causes excessive drying, preventing normal chick growth. Conversely, high humidity reduces moisture loss resulting in chicks that are too large to pip through the shell. Getting incubation humidity right is crucial for maximizing hatch rates.
Ideal Humidity Levels
According to traditional methods, the recommended humidity level is 40-50% for the first 18 days when incubating chicken eggs. For the final 3 days of “lockdown”, humidity should be increased to 60-65%.
However optimal incubation humidity can vary slightly depending on factors like egg size and incubator design. Always follow your incubator manufacturer’s instructions for ideal humidity ranges.
Here are some general humidity guidelines:
- Days 1-18: 40-50%
- Days 19-21 (lockdown): 60-65%
How to Measure Humidity
Incubators may have built-in hygrometers but it’s wise to double check humidity levels. Here are some ways to accurately measure humidity:
- Digital hygrometer with external sensor
- Wet and dry bulb hygrometers
- Weigh eggs daily to ensure correct moisture loss
- Check air cell size when candling eggs
Adjusting Humidity Levels
To increase humidity:
- Add water surface area (water channels, wet sponge)
- Reduce ventilation
- Ensure water temperature matches incubator
To decrease humidity:
- Increase ventilation
- Remove water sources
- Move incubator away from humid areas
- Use dehumidifier if very damp conditions
Signs of Incorrect Humidity
Too low humidity:
- Excessive air cell
- Embryos too small, weak chicks
- Increased hatch failure
Too high humidity:
- Small air cell
- Chicks too big to pip shell
- Chicks suffocate from lack of oxygen
Maintaining Stable Conditions
Avoid abrupt humidity fluctuations. Changes should be gradual, only a few percentage points per day. Locate your incubator away from windows, bathrooms or kitchens. Room temperature, water surface area and ventilation all interact to affect moisture levels.
Proper humidity is essential for incubating healthy chicks. Follow your incubator’s guidelines and measure humidity levels regularly. Make gradual adjustments as needed to maintain 40-50% humidity for the first 18 days, then increase to 60-65% humidity for lockdown. With some monitoring and practice, you’ll be rewarding with a bountiful hatch of happy chicks!
Forced Air and Still Air Incubators
There are two basic types of incubator, forced air and still air. Either one can result in a successful hatch, as long as care is taken to make sure temperature and humidity are consistent. Both are very similar in function and design, with the exception that the forced air incubator has a fan that circulates air over the eggs. For best success, set the forced air incubator thermostat at 99 to 99.5 degrees Fahrenheit and 60% relative humidity. The fan will make sure temperature and humidity are consistent throughout the unit.
A still air incubator can be a little more challenging to manage temperature and humidity, but before the invention of the electronic circuitry and small fans available with a new incubator, countless eggs were successfully hatched in a still air incubator. Set the temperature of a still air incubator to 100-101 degrees F at the height of the eggs. Air will layer, or stratify in a still air incubator, so where the reading is taken is important. Set the humidity slightly higher, 60 to 65% relative humidity during incubation. Check the still air incubator often, eggs can overheat more easily in a still air incubator. Fortunately eggs can handle some variation from the ideal temperature, and tolerate slight underheating better than overheating for more than a few minutes, but the more constant environment you can provide, the better your hatch rate will be.
Hatching Begins in the Egg
The hatching process is one of the niftiest little miracles in the animal world. During the last days of incubation, the chick grows to fill up the entire egg, except for the air cell, the pocket of air at the large end of the egg. At this time, the chick begins to orient itself in the shell and prepare for hatching. Their head and beak are tucked under one wing, with their beak facing the air cell. At about day 19 of a 21-day incubation period, the chick’s head will thrust forward, breaking the membrane between them and the air cell, a process called the ‘internal pip’. The chick begins to take its first real breaths.
By day 20, their lungs are functioning and the chick will begin the serious part of the hatching process. Using the egg tooth, a tiny projection on the end of their beaks, they will begin to peck at the shell thousands of times. The shell has become thinner by this stage, as the chick absorbs some of the calcium from the shell in making its skeleton, and this ‘external pipping’ happens fairly quickly.
Once the chick has pecked through the shell, they will rest for several hours, as their lungs adjust to breathing outside air. Proper humidity in the hatcher is critical at this point; if the membranes dry out and adhere to the chick’s body, it will be more difficult for the tiny bird to leave their shell. During the second stage of pipping, the chick will move inside the egg, turning clockwise in a circle, pecking away at the shell until a circumferential break in the shell is created, known as “zipping”. After this, the chick will push out of the shell, to lay squirming and exhausted on the floor of the hatcher.
You will see the newly born chicks fall deeply asleep for several minutes, then move a bit, then sleep more as they gain strength and flexibility. But it doesn’t take long for them to begin moving around more as their muscles gain strength and coordination. In a successful hatch, 95% of the eggs will hatch within 24 hours. Wait to move the chicks to the brooder until they are dried and fluffy, otherwise they can get chilled during the move.
If you have several chicks that do not hatch, the culprit is likely a humidity issue, either during incubation or hatching. Humidity should be around 50% during incubation and closer to 65-75 percent during the hatch process. Keep in mind that too much humidity isn’t good either. Pay attention to the manufacturer’s recommendations for their unit, and realize that you may have to do a couple of hatches to get a real feel for your incubator.
While it’s tempting to try to help out a chick that seems to be struggling during the hatching process, you can often do much more harm than good. The entire process can take up to 24 hours. Trying to speed things up by removing the shell and tearing the membranes can speed up the drying of the membranes, making it more difficult for the chick or damage the chick’s delicate feathers and skin. Depending on the stage of hatching, the membranes might still be filled with blood that has not been drawn into the chick with the yolk. Tearing the membrane and rupturing the blood vessels will almost always result in a dead, or seriously weakened chick.
The floor of your hatcher is also important. Many of the new incubators have bases that are hard plastic. These are wonderful for being able to clean and disinfect thoroughly between hatches, but they are often too slippery for the chicks to be able to get good footing. If chicks have to struggle too much to be able to get to their feet, there is a good chance they can become spraddle-legged. This means that their legs spread out beneath them, and if left like this too long it can permanently damage their legs. Cut a piece of inexpensive rubber shelf liner to fit the floor of your hatcher. This material is readily available and it can be washed and reused for many hatches. Some Styrofoam incubators have fine wire mesh floors, which will also work for giving new chicks much needed traction.
Once the chicks are dried and fluffed out, it’s time to move them into a brooder. A good brooder should provide protection from drafts and be small enough that the chicks do not wander too far from a heat source and become chilled, but not so small to prevent them from getting away from the heat source if they choose.
Non-slip flooring is also important in the brooder. Many people use shavings with good results, but depending on the size of the brooder, a rubber liner can work well too. Whatever you choose, make sure it’s easy to clean. After the first three or four days, once the chicks start eating well, it’s amazing how much poop they can produce.
When humidity is too high during lockdown in your egg incubator, We show you what to do
FAQ
What humidity is best for incubating chicken eggs?
Ideal Levels: For most eggs, humidity should be around 40-50% for the incubation period and increased to 65-75% during the last few days before hatching. Water Reservoirs: Most incubators have built-in water reservoirs. Fill these with water, as evaporation will increase humidity.
Is 60% humidity too high for chicken eggs?
Ideal Humidity Ranges for Different Eggs
Here’s a general guide: Chicken eggs: 35-55% during incubation, 65-75% during hatching. Duck eggs: 50-60% during incubation, 65-80% during hatching. Reptile eggs: Varies depending on the species, but generally between 60-70% is common.
How much humidity is good for chicken eggs?
Set the temperature to 100.5 degrees Fahrenheit with 50-55 percent humidity.
What humidity should eggs be kept at?
Fresh eggs that are stored at about 55°F with 75% humidity will last for about 2-3 months. Fresh eggs that are stored at 30°F with 85% humidity will last for up to 9 months. It is important to note that the freezing point for eggs is 28°F.