Humidity is a crucial factor in incubating and hatching chicken eggs successfully. The right levels of humidity at different stages of incubation play a key role in embryo development and hatchability. As backyard chicken keepers, maintaining proper humidity levels in the incubator ensures higher hatch rates and healthier chicks.
Understanding Humidity and Its Role in Incubation
Humidity refers to the amount of water vapor present in the air, The humidity inside an incubator comes from the evaporation of water through the eggshell and from an external water source
Chicken eggs need to lose a certain amount of moisture through evaporation as the embryo develops. However, excessive loss of moisture can decrease hatchability. That’s why controlling humidity is essential.
Incubator humidity serves multiple functions:
- Regulates moisture loss from the egg
- Makes the membranes around the chick easier to penetrate during hatching
- Allows the chick to pip the egg more easily
- Prevents the chick from sticking to the membranes and shell
Ideally, humidity should be higher in the beginning, lowered in the middle, and increased towards the end. This fluctuation mimics the process that occurs under a broody hen.
How Humidity Levels Affect Incubation
Here’s an overview of how humidity impacts incubation at different stages:
First 18 Days
- Ideal humidity: Around 50-55%
Higher humidity limits excessive moisture loss during the main growth phase. The developing embryos are very susceptible to changes in humidity at this stage.
Low humidity can reduce hatch rates due to inadequate moisture in the egg. High humidity can also lower hatchability by inhibiting moisture release.
Day 19 Onwards
- Ideal humidity: 65-70%
In the late stages, increased humidity softens the eggshell and keeps membranes moist. This helps the chick pip through the membranes and zip around the shell.
If humidity is too low during hatching, membranes can dry out and stick to the hatching chick, making it difficult to emerge. High humidity can cause drowning, swelling or problems breathing.
How Temperature and Airflow Affect Humidity
Incubator temperature and airflow also impact humidity levels:
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Higher temperatures cause more rapid evaporation of water, lowering humidity.
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Lower temperatures reduce evaporation, leading to higher humidity.
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Higher airflow speeds up evaporation, reducing humidity.
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Lower airflow causes less evaporation, increasing humidity.
That’s why monitoring both temperature and humidity is crucial for incubation. Slight adjustments to temperature or fan speed can help maintain desired humidity levels.
Measuring and Managing Incubator Humidity
Here are some tips for measuring and controlling humidity in your incubator:
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Use a hygrometer to monitor relative humidity levels. Digital hygrometers give the most accurate readings.
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Check and adjust humidity at least twice a day during incubation. Make incremental adjustments and allow time for the changes to stabilize.
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Add an external water source such as a water pan or reservoir to provide moisture if needed. Use distilled or filtered water to fill it.
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Increase ventilation to lower humidity by adjusting baffles or running the fan for longer durations.
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Use incubator vents and cooling fans cautiously as they can drastically reduce humidity.
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Add moisture-absorbing desiccants like silica gel packs to reduce excessive humidity if needed.
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Calibrate hygrometers periodically to ensure accuracy. Improper humidity is one of the main reasons for poor hatch rates.
With close monitoring and incremental adjustments, you can maintain the ideal humidity levels for your chicken eggs throughout incubation. Pay extra attention to humidity in the critical last few days of hatching to get the highest hatch rates possible. Proper humidity gives baby chicks the best start on their journey to become happy, healthy additions to your backyard flock!
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.
Choosing Eggs, Storing Them, Temp, Humidity & More! Hatching Chicks Step By Step! | Hal’s Hatchlings
FAQ
What is the best humidity for chicken eggs?
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.