History:
The Hen Egg is the first in a series of fifty-two jeweled eggs made under the supervision of Peter Carl Faberge for the Russian Imperial family. It was crafted and delivered in 1885 to the then-Tsar of Russia, Alexander III. The tsarina and tsar enjoyed the egg so much that Alexander III ordered a new egg from Faberge for his wife each subsequent Easter.

The crafting of the first Imperial egg is attributed to Erik Kollin of Faberge's shop. The egg is made of gold, completely coated with opaque white enamel to look like a real egg shell. A thin band of gold where the two halves of the shell are joined is visible around the middle of the egg. The two halves of the outer shell fit together in a bayonet-style fitting which opens when twisted to reveal the surprise.

Surprise:

The two halves open to reveal a gold yolk with a matte finish, containing a varicolored gold hen with ruby eyes. The hen is hinged on the tail feathers which allows it to also open up to reveal two additional surprises which are now missing. The first of these was a gold and diamond replica of the imperial crown. Suspended within the crown as the final surprise was a tiny ruby pendant. 
The egg is currently located in Russia as part of the Vekselberg Collection.