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Candling Fresh Eggs
Week 1 of Incubation
Weeks 2 and 3
Week 4 of Incubation

Fresh Eggs: Old Eggs
How Can you tell an Old Egg?
If the egg is not rotten, you can tell it's age quite reliably by looking at the air cell.
As time goes by, the contents of the egg begins to evaporate because the shell is porous, and since the egg shell can't shrink, this causes the air cell to get bigger.
The air cell of a fresh egg should be small - no bigger than a centimeter across for a medium-large duck egg.
Always wash eggs in very warm water. If the water is colder than the egg, the egg will tend to draw water into it - and it will draw in dirt at the same time.
Above Left: About two weeks old. No longer useful for hatching, but still fine for eating. Above Right: 4-6 weeks old. Still edible.
While eating eggs can keep safely in the fridge for 2-3 months, sometimes, an egg will “go off”. It is usually because some dirt got in somehow - through an unnoticed crack, or right through the shell. Eggs that have gone off are usually easy to detect: they will be dark inside, and if you smell the shell they will smell foul. Wrap these carefully in plastic and discard them. It is extremely rare for eggs like this to affect any other eggs, so the remaining eggs in the batch will usually be fine.
This egg was allowed to sit on the counter for a month. It was the only one that went bad out of a dozen. The line above the air cell is a pencil line made to mark the location of the air cell three weeks before.
How can we tell the age of an egg in water? Watch this rotten egg being candled. Note that the contents of the egg don't seem to move around.
Can't watch the movie? Download the Quicktime media player.

farm/candling/too_old.txt · Last modified: 2020-05-09 15:02 (external edit)