When your hens are laying well, they will produce a new egg every 25.5 hours. For something as big, complex and perfect as an egg, that's pretty amazing.
An egg is made from the inside out. The yolk develops first, and is then wrapped in a layer of egg white, before being neatly packaged in a protective egg shell.
Brahma chick next to an unhatched egg
The beginning of an egg is a tiny ova which takes a week to grow into a proper egg yolk. If you cut a boiled egg in half and look at the yolk, the dark rings were layers made during the day and the light layers during the hours of darkness. Strange but true!
When the yolk is ready it is released along the oviduct. The first part of the oviduct is where the egg white (albumen) is added. The egg white mainly consists of protein, water and minerals.
Then the egg carries on along the oviduct where it grows two connecting strands at the top and the bottom called chalaza, which anchor the yolk to the shell keeping it in the centre of the egg.
The next stage is for the shell membranes to form around the white. After this the egg continues down into the uterus where the shell is added. This is made from calcium carbonate, the same substance that makes up marble, chalk and shellfish shells. The shell is a great bit of design, thin but incredibly strong.
Mike, 6 May 2020
Thank you. This helped me with many lockdown sanity questions about life.