4 Factors That Influence Hatching

Worried about hatching chicks?

We are here with the ultimate guide about main factors involved in hatching and how you can monitor each factor.

The poultry industry relies on a regular supply of day-old chicks. If you want to maintain chick production, you must keep fertility and hatchability of eggs in mind. Fertility is the percentage of incubated eggs that are fertile. Hatchability is the percentage of those fertile eggs that hatch successfully.

While incubating an egg, you must control the following factors for successful hatching.

  • Temperature
  • Humidity
  • Ventilation
  • Egg Turning

Temperature & Humidity

If the temperature and/or humidity are not properly controlled, you will get poor hatchability. If either of the two factors is too high or too low, it can interfere with the normal growth and development of the embryo.

Minor fluctuations of less than half a degree in temperature can be tolerated. However, you must not let the temperature fluctuate more than a total of 1 degree celsius This can affect normal development.

You can obtain a precise temperature reading by placing the thermometer bulb on top of the eggs. The temperature must be measured at the top of the eggs because this is where embryos develop. However, you must not let thermometer’s bulb touch the eggs as this may give you an incorrect reading.


Ventilation is equally important during the incubation process. Unequal ventilation can affect hatch rates significantly. Oxygen must enter the egg and carbon dioxide must pass out through the egg shell for normal embryo development. When chicks hatch, they need higher levels of oxygen. Therefore, the air vent openings should be gradually opened to provide an increased supply of oxygen to the embryo.

Egg Turning

Eggs should also be turned at least 4-6 times during the incubation process. However, you must remember not to turn eggs during the last 3 days before hatching. This is because the embryos are moving into their hatching position and don’t need to be turned.

If you are turning eggs by hand, it can be helpful to mark the eggs. For example, you can place an ‘X’ on one side and an ‘O’ on the other side of the egg. This ensures that all eggs have been turned.

Another precaution to keep in mind is that your hands should be free of oil or dust while turning the eggs. If eggs are soiled with grease, it can affect hatchability. Also, you must be careful so as not to shake the egg during its first week of incubation. If the egg is shaken severely, delicate blood vessels may rupture, killing the embryo.

If you want to make turning easier, you can invest in an automatic incubator. It will automatically turn the eggs at regular intervals, thus saving you the hassle. An automatic incubator is a good option in case you forget turning the eggs or might be busy somewhere else.


Now you know the main factors that influence hatching and how you can control them. If you have any questions, please feel free to ask in the comments box. Our experts at Poultry Works will guide you through.