Why Won't My Chicken Eggs Hatch?
Many people struggle with hatching chicken eggs and puzzle about why they are not hatching. Hatching eggs is not always an easy thing and even poultry producers do not have a 100% success rate. Below are the common problems people experience when trying to hatch chicken eggs.
Chicken eggs take about 21 days to hatch. If you have a chicken egg that is more than 24 days old, it will not hatch. Other species of bird eggs take longer or shorter.
Grocery Store Eggs
Sometimes people think they can buy eggs from the grocery store and hatch those. It will never happen for several reasons. Firstly the hens that lay the eggs are not exposed to roosters, as such the eggs are not fertile. Secondly the eggs are collected immediately after being laid, and refrigerated, as such even IF they were fertilized, a chick could not possibly survive, as normally they must be incubated at warm temperatures.
As mentioned above hens lay eggs whether or not a rooster is present. Even if a rooster is kept with the hens, not necessarily will all the eggs be fertile, older roosters, or ones who have health concerns, will not have mated with the hens. The same will happen when the rooster to hen ratio is off and there are too many hens for the rooster. With a rooster the typical fertility rate can be from 55% - 95%, and even then not all of the fertile eggs are likely to hatch. See below on How to Candle an Egg.
Hen didn't Sit
Not all hens will sit on their eggs long enough to keep them warm. Some chicken breeds are known for being “broody”, meaning they are more likely to raise chicks, while other breeds only sit in the nest long enough to lay an egg then walk away. Typically a broody hen will lay several eggs before she starts sitting on them. Rather than using a broody hen to hatch eggs, one can use an incubator.
photo source Hens who are broody will only get off the eggs for a few minutes to eat and drink.
Hatching eggs requires some very specific measures. The temperature must be perfect, the humidity must be perfect, the eggs must be turned at the appropriate time, and they must be carefully positioned.
Temperature – This must be kept between 99.5 F and 100 F at all times, if temperatures are too high or too low for very long, the embryos will die and will not hatch.
Humidity – Humidity effects the development of the air bubble inside the egg and must be correct towards the time when the chick is ready to hatch or problems will develop. Each Incubator will have a feature for keeping the air inside it at proper humidity, typically water is put in a small cup.
Turning – Eggs must be turned two or three times a day in order for the chick to develop, however turning must stop in the last 3 days of incubation. The easiest way of remember if eggs have been turned, or how far to turn them is to mark both sides, one with an X, and one with an O (or similar markings). Some incubators are self turning, others will require a human to turn the eggs.
Position – The eggs should be carefully placed so that, while they are on their side, the larger egg is slightly higher than the more pointed end.
*How to Candle an Egg
To check if an egg is fertile one can “Candle” it after it has been incubated (either by a hen, or in an incubator) for about 3 – 4 days. This is done by putting a bright lightbulb in a box with a whole cut to allow some light out. The egg is held over the hole and if a cloudy area can be seen it is chick developing, if it is clear and the light passes through evenly, then the egg either was not fertile or the growing embryo has died.
Some people will recheck again at 7 days, in fact you can candle them safely at any time but may not want to risk dropping them. You may even be able to see a network of veins developing if your light is strong enough. *Eggs should not be out of the incubator for more than ½ hour. As you get more familiar with candling, you may note some problems (such as bacteria grown in side eggs) can also be seen, but as a general rule a clear egg after 7 days does not hold a growing embryo and should be discarded, until you are familiar with other problems keep any egg showing anything else for up to 24 days.
Other Information and Links
Do not attempt to hatch eggs unless you have a place to brood chicks, and are prepared to do so.
Hatching Eggs can be purchased at some livestock feed stores, livestock auctions, or from a producer.