What's up with the humidity?

[Titanpaul726]

55% humidity for the first 18 days, then 65% for the last 3-4 days works well for me. I may try to up the level to 70% on the next batch, but those numbers seem to work well. I'm not really into all the tinkering, record keeping etc..... I just want to hatch the viable eggs I put in the incubator. I may change my tune if I ever want to hatch expensive stuff, but the K.I.S.S method is working the best for me.

 

[lazy gardener]

The incubator is a controlled environment as everyone knows. Outside of the incubator is a variable environment that can change the incubator environment.....if you let it. Most homes come with environmental controls to limit the changes in temperature and humidity as with my home. Albeit not perfect, I have placed the incubator in a room where I can control the temperature changes within 2 degrees with no direct ventilation on the incubator. Temperature is rock solid in the incubator as is the humidity. With the aforementioned in mind, what other influences could there be to a successful hatch? I hear that there is a difference between styrofoam or other materials and besides the porosity of the styrofoam vs plastic, wood or metal, what is the difference?

Bubba: You make a valid point: 30% is 30% no matter what kind of container it is in. The one variable that interplays with that is egg shell integrity. Some shells are thicker, some more porous. I'm just thinking out loud here, but I also think that there are other internal factors that affect how the egg interacts with the humidity in the incubator. That being the health of the hen and her nutritional status when she laid the egg, as well as the age of the egg. I think there's a lot we don't understand about how all of this works together at the cellular level, as well as the viscosity of the layers that make up the albumen, and the integrity of the various membranes of the egg. I think that what PP are saying, is that you should choose a humidity level for the first 18 days. After doing that, the next step is to keep an eye on the air cell size, and tweak that humidity accordingly. Hatching eggs is as much a science as it is a cook book recipe. Once you have a hatch or two under your belt, and especially if you take the time to do eggtopsies on your failures, you'll develop a sense of what needs to be done in a particular circumstance with a certain set of eggs to maximize your outcome. Now, after I've said all of that, I will tell you that I am a novice! I'm flying by the seat of my pants here, and totally marvel that I can take an egg, and cook it for breakfast. Then I can take an other egg that looks identical to the one I just enjoyed for breakfast, and cook it a bit slower, and a bit longer... (21 days) and end up with a perfect little chick. Such an incredible master piece of design!

P.S. I aim for 30% through day 18, then jack it up to 65%.

 

[WalnutHill]

55% humidity for the first 18 days, then 65% for the last 3-4 days works well for me. I may try to up the level to 70% on the next batch, but those numbers seem to work well. I'm not really into all the tinkering, record keeping etc..... I just want to hatch the viable eggs I put in the incubator. I may change my tune if I ever want to hatch expensive stuff, but the K.I.S.S method is working the best for me.

Yep, if you have a system that works, then stick with it whether anyone else does it the same way or not!

I have a homebuilt incubator, and on the first run, so I am logging data to determine the operating profiles as each tray is a little different, the upper trays are cooler and more humid, with 1/2 degree and 1% difference between trays.

 

[Ridgerunner]

You’d think that the environment inside the incubator is the environment, but not so. Some of the reasons it varies have already been mentioned, some not. Egg shell porosity is one. The density of the egg white can vary a lot. Some are pretty thin, some pretty thick. How long and under what conditions the egg has been stored plays a part. It may have already lost a fair amount of moisture by the time you start. How high are you above sea level? Air pressure can vary quite a bit.

Still air versus forced air can make a difference. The temperature and humidity of the air entering the incubator makes a difference. Cold dry air will draw more moisture as it warms up and comes to humidity. Where are your vents and are the plugs in? The more air exchange you have the more moisture will be sucked out. Is the incubator sitting where sunlight can warm it? Is the AC running or are you heating your house? Where is the incubator sitting in relation to air vents or return ducts? Seasons affect it. Are you incubating in a wet spring or a dry summer?

Manufacturing tolerances can vary. Does the lid fit as tightly as it should? How do you turn the eggs? Are you constantly opening the incubator to turn them and let humidity out or do you have an automatic turner? How fast does your individual incubator return to levels after it is opened?

I’m sure there are other things but I’m tapped out. One important note, the perfect humidity can be different for different eggs because of the variety in the eggs and how or how long they are stored. Your goal is to get the humidity that works for the majority of the eggs. It’s possible to have some eggs in the same hatch where the humidity is too high or too low for individual eggs where for most it is really good.

 

[BobDBirdDog]

Ditto on all the above, I can have a consistent 50% humidity, but when I open my door to air the house, the humidity will rise or fall according to the new introduction of the outside climate, daily, hourly, daytime, nighttime...etc. With the doors shut and depending on the source of environment choice for my house (Heating/Cooling) will factor in to my incubators humidity as well.

In short, just check it every now and then and make adjustments if needed.

 

[BubbaLikesIt]

That is the answer that I was looking for. All things being equal, temperature, humidity, the alignment of the Chicken star with Venus and the moon in retrograde. If you have stable temperature and humidity, out of direct sunlight with minimal influence from the outside environment....... then it is what it is. Now, as mentioned above by RidgeRunner, atmospheric pressure is something I have not taken into consideration and we do live at 3000' above MSL and that may or may not have an effect. So basically this comes down to the egg. The egg dictates what your next move is. Assuming you have done your job diligently and created the desired constant environment within the incubator, the egg tells you how much humidity to use and that won't happen for 10 to 14 days.

Now with that out of the way, starting out at 45% humidity would be a good level until you can see what the egg is doing?

 

[scflock]

That is the answer that I was looking for. All things being equal, temperature, humidity, the alignment of the Chicken star with Venus and the moon in retrograde. If you have stable temperature and humidity, out of direct sunlight with minimal influence from the outside environment....... then it is what it is. Now, as mentioned above by RidgeRunner, atmospheric pressure is something I have not taken into consideration and we do live at 3000' above MSL and that may or may not have an effect. So basically this comes down to the egg. The egg dictates what your next move is. Assuming you have done your job diligently and created the desired constant environment within the incubator, the egg tells you how much humidity to use and that won't happen for 10 to 14 days.

Now with that out of the way, starting out at 45% humidity would be a good level until you can see what the egg is doing?

I think 45 is a good start. I'm lazy, and don't meticulously measure the air cells or weigh the eggs. I started at 45, dropped to 35 on my next batch, then settled at 40-42 where I had my best success

 

[BubbaLikesIt]

Right on. That is what I'm going to do. If I don't have every egg hatch, I know a Rooster that is in big trouble.

 

[scflock]

Right on. That is what I'm going to do. If I don't have every egg hatch, I know a Rooster that is in big trouble.

That's another variable. My Polish is throwing about 40% infertile. He has his favorite hens

 

[Egghead_Jr]

I scanned through this thread and likely missed it being mentioned. There are variables that are out of your control which are your home environment and eggs but the number one reason for differences of opinion on humidity is the lack of calibrating hygrometers. Seriorously, people will purchase three hygrometers and keep all in the incubator with none reading the same but not bother to perform a simple salt test on one of them. Easy to do and gets you calibrated so at least we're all talking the same language. If your hygrometer is 10% off and you never salt tested to calibrate then what humidity works for you is not the same as what works for me.

Hygrometers built into the lower end incubators are typically worthless and not able to be slat tested so a small unit needs to be purchased an placed inside.

Just my 2 cents and likely not worth that.