Egg Production: Candling

The contents are examined without cracking the shell. The condition of the shell, albumen and yolk are all checked. Inferior eggs are removed.

In modern operations, to detect shell cracks, eggs are checked sonically. In a matter of seconds, tiny probes tap each egg 16 times and ‘listen’ for the sound it makes. A fully intact egg has a high pitch and a sustained ring. A thud indicates a crack and the egg won’t be packed.