Incubation is one of the most important parts in raising chickens. I have done much research on this and have alot of trial and error experience. I hope the information I have gathered can help those of you who just learning or just have some questions. If you can't find what you are looking for here on my page, drop me an e-mail and I might be able to help.
Got your Eggs?
Your eggs need to settle for at least 24 hours if they came through the mail. This allows the air-cell inside the egg to return to it's normal size. Eggs should always be stored with the pointy end down while they are "in the hold". It's a good practice to follow and it will help your hatch!!! If I receive eggs that are getting old, I may only let them settle overnight.
Incubator ready?
By the time you have gotten your eggs your incubator should have been running at least 24 hours. A week is even better. This gives you time to learn what's going to happen in your incubator and allows you to make any necessary adjustments before setting your eggs. A sure-fire way to ruin hatching eggs is to put them in the incubator without having it properly adjusted. If the eggs reach an internal temperature of 105 degrees you can kiss them good-bye. Take note that I said "internal" temperature. Don't confuse internal egg temperature with internal incubator temperature. The temperature in an incubator changes constantly, rising and lowering. The temperature inside the egg will be an average of this temperature swing in your bator.
Temperature & Humidity
This is plain and simple, yet the MOST important part of hatching.
Still-air incubator (no fan):101.5 degrees measured at the TOP of the eggs.
Fan Forced incubator: 99.5 degrees measured anywhere in the incubator.
Humidity: 60-65% for the first 18 days, 80-85% for the last 3 days.
You can sneak by with humidity numbers that aren't very accurate, but the combination of poor humidity and temperature will definately cause problems at hatch time. If your temperature is not accurate you will DEFINATELY have problems at hatch time. The bigger the deviation from the proper temperature, the bigger your problems will be!
Is your Thermometer accurate?
I'm willing to bet that it isn't. Thermometers go bad. Keeping the temperature accurate can be a struggle, even with very good thermometers. I've thrown away many thermometers in past years that I had considered reliable.
A nice part about running a big incubator over an extended period is that you can tweak the temperature regardless of what thermometers tell you. After the first hatch, you can raise or lower the temperature by what the hatch tells you. If they hatched early the temperature needs to be lowered. If they hatch late the temperature needs to be raised.
You can check your Thermometer this way. Keep notes on everything you do during the incubation period. As you learn you'll have these notes to look back on. They will be the most valuable tool that you can have. It won't be long until you can say "I know what happened, all I need to do is change this one little thing". Soon you will be able to make adjustments by knowing what to do, instead of guessing!!!
How do I check humidity?
Humidity is checked by way of a hygrometer (wet-bulb thermometer) in conjunction with a regular "dry-bulb" thermometer. A hygrometer is simply a thermometer with a piece of wick attached to the bulb. The wick hangs in water to keep the bulb wet (hence the name "wet-bulb thermometer"). When you read the temperature on the thermometer and hygrometer, you must then compare the readings to a chart to translate from wet-bulb/dry-bulb reading to "percentage humidity".
From the relative humidity table, you can see.....
60% humidity reads about 87 degrees on a wet-bulb at 99.5 degrees.
60% humidity reads about 89 degrees on a wet-bulb at 101.5 degrees.
80% humidity reads about 93 degrees on a wet-bulb at 99.5 degrees.
80% humidity reads about 95 degrees on a wet-bulb at 101.5 degrees.
Getting your humidity to become as accurate as your temperature is nearly impossible. It is almost completely impossible with a small incubator. Try to get your humidity as close as you can, and you'll be fine. Just being aware that humidity is important, and trying to get the numbers to come in close will be a huge help to your hatch.
If you can hold within 10-15% things should turn out fine.
Temperature on the other hand, is CRITICAL!!!!! I hate to beat this point to death, but a small deviation in temperature (even a couple degrees) can and will ruin a hatch. Or, at least turn a potentially great hatch into a lousy one.
An important point about incubator humidity...
As seasons change, so goes humidity. When you are incubating eggs in January and February it will be very difficult to maintain a humidity that is as high as you like. That's because the outside humidity is so low. By the same token, when you are incubating in June and July the outside humidity is usually much greater and the humidity in your incubator will most likely get much higher than you would like. Hatching problems will change as the season progresses. If you are doing things the same way in July as you were in January, you have to expect different results. All I am trying to say here is that your incubator humidity changes directly according to the outside humidity. Low outside, low in the bator. High outside, high in the bator. To adjust for these problems, you need to change the surface area of water in your bator.
Surface area?
Surface area is "the amount of surface of water exposed to air in your incubator". The depth of water has absolutely no bearing on the humidity in the incubator (unless the depth is zero). If the humidity is too low in your bator, add surface area. Place another pan of water in the incubator, or some small, wet sponges. This will help. To decrease the humidity, remove surface area. Use smaller containers of water, or undo some of the things you've added.
The incubation period for chicken eggs is 21 days. You should turn your eggs at least twice a day for the first 18 days, and stop turning after the 18th day. This allows the peep time to orient itself inside the egg before pipping.
After day 18, KEEP THE INCUBATOR CLOSED except to add water. This will help bring the humidity up to help the peeps hatch. I know it will kill you not to open the incubator 1000 times when it's this close to hatch time, but it's not good for the peeps. If you haven't bought an incubator yet, invest the extra couple bucks in the picture window model. Then you can "see it all" without causing harm to your hatch.
On Thermometers...
Good thermometers can be found at a few places. Camera stores carry reliable thermometers. Refrigeration parts/supply stores/warehouses and Scientific supply outfits carry reliable thermometers as well. The best investment you will ever make in your hobby is a good, accurate thermometer for incubation.
Tip...When picking out a thermometer from a batch of them, you should look at them all to see if they are reading exactly the same temperature. If not, save your money, or make sure they can be calibrated.