To see the rarity of a pet, you can go to your hatchery, then click on "creatu list". The higher the percentage of rarity, the more common the pet is. And the colors go in order from most common (natural) to least common (albino). Also, the Easero is a seasonal egg, so it only comes out at easter time; I would hold onto those ones if I were you. Welcome to the site, accelia! :)