This is the idea that a hen is merely an egg's way of making another egg.

ECONOMIST: Ageing

Just as a hen is about to lay an egg, she applies a liquid coating around it that naturally protects against contamination.

FORBES: Natural Protection

Ideally, when a chick becomes a candidate to become an egg-laying hen, it is put in a clean environment with clean water and feed, he said.

CNN: STORY HIGHLIGHTS

So enthralled was Fedorovna with the piece--an enameled egg with a golden yoke, golden hen, miniature diamond crown and ruby egg inside--that the czar commissioned a new egg every Easter.

FORBES: Faberge Egg Goes Back To Its Nest

The male hen harrier is famous for its spectacular looping "sky-dance", part of an elaborate mating ritual.

BBC: Walkers urged to spot hen harriers