Excuse me everyone, pardon the interruption, but I think it's really important that we all know about the existence of ancient Egyptian egg ovens: an ingenious early incubation technology that enabled the Egyptians to hatch tens of thousands of chicken eggs with mud and fire

Chickens likely arrived in Egypt about three to four thousand years ago via trade with Mesopotamia. By ~700 BC, they were becoming a staple of Egyptian cuisine; demand was increasing. But all the time the birds spent brooding put constraints on their productivity.

To solve this dilemma, Egyptians experimented w/ artificial incubation, trying to replicate the conditions eggs enjoyed beneath a hen's plumage. They built adjoined sets of two-tiered, vented mud brick ovens warmed by smoldering piles of dung & straw: eggs on bottom, fire on top

The complexes also had rooms for oven masters & egg-turners to live and rest. Eggs required regular rotation to prevent membrane attachment and deformities.

In the final stages, hatchery workers would hold eggs to their eyelids to gauge their temperature & readiness to hatch.

A single large egg oven could allegedly hold 15,000 eggs; the biggest incubation complexes could hatch 80,000 eggs.

Some researchers have proposed that the Egyptians also used these hatcheries to breed ibises, which they considered sacred and mummified in huge numbers.

Greeks and Europeans who encountered egg ovens were astonished and mystified, especially as the Egyptians were somewhat secretive about their methods. Whereas Europeans relied entirely on hens to hatch eggs in warm seasons, the Egyptians were mass-producing chickens year-round.

Early Egyptian incubators have endured for millennia. In the early 20th C, egg ovens in Egypt produced an estimated 90 million eggs / year. Hundreds are still used in some parts of Egypt today, albeit with electric or petrol lamps instead of dung fires.

Lenny Hogerwerf; FAO

Sources and Further Reading

http://www.fao.org/3/al684e/al684e00.pdf

http://www.aviculture-europe.nl/nummers/12e03a08.pdf

https://www.atlasobscura.com/articles/egypt-egg-ovens

https://www.tandfonline.com/doi/abs/10.1079/WPS19460032?journalCode=twps20

https://www.tandfonline.com/doi/abs/10.1079/WPS19670031?journalCode=twps20

https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1474-919X.1966.tb07268.x

https://teachingwiththemes.com/index.php/2019/01/15/what-amazing-egyptian-chicken-hatcheries-can-tell-us-about-perceptions-of-other-places/