With the right equipment and incubation practises, incubating and hatching chicken eggs is relatively easy and very rewarding. It takes about 21 days from setting to hatching.
Eggs need to be chosen with care and should represent the best standard to preserve the breed.
The eggs can be stored before setting and should be kept at a stable temperature and turned twice a day. A cross in pencil is the best way to mark an egg. Eggs for hatching can be stored for up to 10 days but the sucess rate of the hatch will decline the older the eggs are. It is more important that the temperatue and humidity are stable for eggs in stage than the actual temperature they are stored at. The ideal temperature to store eggs is between 12 and 16°C with a humidity between 60 and 80%. Humidity is far more difficult to control than temperature. Egg should also be turned back and forth rather than rolled continuously in the same direction. If you are not able to commit to turning the eggs by hand 3 to 5 times a day then i suggest you buy an incubator with an automatic egg turning mechanism
The secrets to sucessful incubation are:
1. Clean and accurate equipment. I use a forced air incubator with both an elctronic thermostat and a glass bulb thermometer to monitor temperature. more than 1°C variation in temperature will badly effect a hatch and more than 2 or 3°C probably means nothing will hatch at all. It has an automatic egg roller which can be put on a timer so it turns itself off on the correct day. Hygiene is essential, clean eggs with no cracks to allow bacteria inside the egg and a clean incubator will improve hatch and surviveability rates.
2. Clean , well chosen eggs with no cracks and good colour from healthy parents on a good diet. I would add that it is not a good idea to use small eggs from a pullet that is just coming into lay as they may have no yolk and small chicks will take longer to mature and grow. Very large eggs are not a good idea unless you are sure of the older hens fertility and have candled the egg to make sure it has only a single yolk.
3. Patience. A stable enviroment with the minimum of fluctuations in temperature and humidity is most likely to produce the best hatch rates. An electronic thermostat which can keep very accurate control of the temerature is a must, Adequate ventilation is important, the air inside the incubator should change gradually for fresh air. The chicks inside the egg will stil need to respire , oxygen passes throught the pourous shell and CO2 passed out. Make sure you leave the eggs and the incubator well alone during the first 10 days and resist the temptation to peek, the first 10 days is crucial and temperature fluctuations during this time are more likely to affect hatch rates. Eggs should be candled at day 10 and any clear eggs removed.
4. Dont forget to turn the egg roller on or to turn the eggs by hand and also to turn the roller of on day 18 or stop turning the eggs.
I add water at the correct temperature (38.1 °C) into the water tray to increase humidity for hatching. After temperature and hygiene, humidity is one of the biggest factors in hatch failure. If the humidity is to high durning the earlier stages of incubation the egg will not lose enough moisture and the chick will be to large to hatch sucessfully. If the humidity is to low the chick will be to dry to hatch easily. Here in the UK i have never added water to the first stage of incubation, only at day 19 to assist with the hatch. i have always had very good hatch rates using this method, if you have a lot of big fully formed chicks dead in shell then to high a humidity is probably the cause. If humidity they will sruggle to emerge from the egg and may end up with large bits of shell or membrane stuck to them. An egg needs to lose approximately 13% of its mass during the 21 days of incubation, this helps to form the air space in the egg and to provide enough room for the chick to manouvre inside the egg before hatching.