Your precious Monster Egg is carefully coddled in the Nursery. When will it be ready?
~ In-game description
The Nursery is a Structure used to incubate eggs that have been created by the Breeding Structure. It is unlocked at Level 1. It is used in the start of the game as part of the tutorial of breeding a Stogg. When the egg hatches, you can place it or sell it. Also, you can share the egg you had hatched on Facebook if you have a Facebook account.
When an egg is being incubated, it will show a shaking animation.
Monsters bought from the Shop do not require incubation whether or not the monster was bought with coins or diamonds.