Thousands of years ago, Egyptians artificially incubated eggs by building two-story brick incubators and lighting fires above.
Illustration of an egg incubator in ancient Egypt. Image: Amusing Planet
Nowadays, chicks on farms are almost never hatched by their mothers. Instead, they are incubated using artificial heat in large electric furnaces called incubators, devices that can hold hundreds or even thousands of eggs at a time. Electric incubators are a modern invention, but artificial incubation has been around for thousands of years.
The ancient Egyptians were the first to use poultry incubators. They make a strong impression on foreign tourists who have never seen anything similar.
Many visitors have left cryptic notes about the strange method the Egyptians used to hatch chicks. Because they are rarely explained in detail about how the incubator works, they have to guess and are often wrong.
One writer suggests that the Egyptians sat on and incubated eggs. Monk Simon Fitzsimons, who came to Egypt in the 14th century, wrote that chickens were born from eggs through fire, without the need for a rooster or hen. He did not know that the eggs were fertilized by the rooster in the traditional way before being placed in the incubator. Even the Greek scientist Aristotle wrote about incubators, claiming that eggs were buried in piles of dung, around the 4th century BC.
The first travel book that many people read had a relatively realistic description of the Egyptian incubator The Travels of Sir John Mandevillepublished in 1356. “There was a common building in the city filled with small furnaces, and the women of the city brought eggs from chickens, geese, and ducks to put into the furnace. The caretakers of the building covered the eggs with heat. of horse dung, without hens, geese, ducks or any other poultry. After three weeks or a month, the women returned to take the chicks and raise them, so that the whole area was full of poultry.” Mandeville wrote.
French naturalist and scientist René Antoine Ferchault de Réaumur provided the first accurate description of incubators in 1750. Réaumur traveled to Egypt and visited many incubators, observing farmers at work.
A typical Egyptian incubator is a brick structure about 3 m high, consisting of a long central corridor with rooms on either side and arranged in two floors. The two floors are equally large, with an entrance large enough for a person to crawl inside. Eggs are located on the ground floor, placed on cushions made of flax or straw. The upper rooms are used to light fires, using cow and camel dung mixed with straw. This allows the fire to burn more slowly in a more controlled manner.
The keeper usually lights the fire twice a day, depending on the weather, and rotates the eggs so they are evenly warmed from all sides. This continued for about two weeks, then they put out the fire. At this point, the embryo’s organs are complete and the embryo itself produces enough heat to continue the incubation process, which takes another week to complete. Finally, the eggs hatch on the 21st day.
Returning to France, Réaumur tried to build an incubator using the Egyptian method, but due to the cooler European climate, he was not as successful as the Egyptian farmers. After Réaumur’s death, the incubator continued to be developed by Abbé JeanAntoine Nollet, followed by Abbé Copineau, who improved Réaumur’s design by using an alcohol lamp to warm the eggs. It was not until the late 19th century that the first commercial incubators appeared.
A traditional Egyptian incubator uses oil lamps to warm eggs. Image: Lenny Hogerwerf/Atlas Obscura
In the 21st century, in Egypt, hundreds of incubators still use traditional methods developed thousands of years ago, although manure has been replaced by oil lamps and electric heaters. Farmers still do not use modern equipment such as thermometers or thermostats to regulate the temperature in the incubator.
A skilled incubator can gauge the temperature by applying the egg to the eyelid and letting the eye feel the heat. If it’s too hot, the eggs will be sprayed with water. To check the egg’s development, the worker just needs to hold the egg up to a light source such as a lamp. The eggshell is thin enough for them to see inside. These skills are passed down from generation to generation by some families and kept secret from outsiders.
However, Egypt’s traditional incubators may soon disappear. According to a survey conducted by the Food and Agriculture Organization of the United Nations in 2009, all incubator owners interviewed expressed a desire to upgrade to modern incubation methods due to higher hatching rates.