I had a feeling that this topic would explode due to the release of the Easter Eggs. I was right. ...then again, that isn't really saying much since it would be obvious.
Easter egg hatch from Level 5-level7. Most of eggs hatch at 5. So, check your Pokémon collection in your profile, you will see a green arrow at the top right, click on it and it will hatch as your current one hatches at level 5, I think.