Automatic Egg Incubator

My elder brother is a high school biology teacher, an entomologist, and a zoologist. We made many projects together, he has the biological knowledge, the wisdom, and the patience, and I have the electrical and electronic knowledge.

This is one of our projects, an egg incubator. This incubator can hold 25 chicken eggs, and it is heated electrically using bulb lamps. This project can be used at home, in a classroom for students, or in a small farmhouse. It is possible to use the incubator for different types of eggs, chicken, duck, turkey, quail, etc.

The incubator consists of three parts, the box, the electronics, and the electrical part. It is important to state that me and my brother love recycling, so most of the parts used to realize this incubator are salvaged from scratch.

The wooden box is made of wood parts salvaged from a wooden closet. The dimensions of the box is 40x40x65 cm. At one side, it has a door with plexiglass that can be opened and closed smoothy. At the other side, it has a wooden cover that can be removed for cleaning.

Six holes are drilled at each side of the box as can be seen in the pictures. These holes are used to enter fresh air into the incubator. As can be seen clearly in the pictures, it is possible to plug some of the holes with electric tape to prevent quick heat loss. Close/open the holes according to the ambient temperature and the season.

Four aluminium shelves are mounted at the bottom of the box as well as at its upper side. The lower shelf is used to hold the egg trays. The upper shelf is used to hold the fan as well as the bulb used for heating. The electronics is fitted into a small wooden box placed on the roof of the incubator.

The controller is placed in a wooden box at the roof of the incubator. The controller consists of a 2 Amperes 220v-12v transformer, a rectifier circuit, and the OPAMP circuit. the opamp circuit was improvised, but looks similar to the figure here (reference: https://www.eleccircuit.com/opto-thermo-control-relay-switch-with-ic-741/).

Put the incubator in a location with stable temperature. Avoid locations near the windows and air vents.

To keep the humidity inside the incubator, put some warm water to the water pan.

Calibrate the incubator temperature to be around 37.2 and 38.9 degrees Celsius for 24 hours before incubating eggs.

The thermometer should be close to the eggs.

NOTE: Lower temperatures avoid embryos from developing, and higher temperatures kill the embryos.

You can incubate the eggs within 7 to 10 days after they have been laid; but note that the viability decreases with passing time.

You need to wash your hands every time you want to handle the eggs or touch the incubator.

Put the eggs carefully on the shelves with proper spacing. The eggs need to be lying on their sides, with the larger ends of the eggs slightly higher than their pointy ends.

Note that the temperature will drop instantly when you put the eggs; no need to correct this change.

You need to write down the number of the eggs and the date of their placement in the incubator.

It is important that you turn the eggs at least three times in a day. This will remove the effect of temperature change. While doing that, check each egg for cracks and remove cracked and spoiled eggs. Better to change the positions of the eggs around the incubator.

Check the state of each egg by pointing it to light and checking its inside carefully after 7 to 10 days.

While the humidity is kept around 45-50% during the incubation, you need to increase this humidity at the final three days of the incubation to 65%.

When chicks start to hatch, keep hatched chicks inside the incubator for about 6 hours. This will ensure they are dried. Remove dried chicks to another box with fixed temperature at 35 degrees Celsius.

After using the incubator and removing all the empty shells and the chicks, you need to clean it carefully and ensure its sanitation. This is VERY important, because diseases can overcome the eggshells and reach the embryo.