Finish a Collection
When you finish a collection in Hatchlings, a green checkmark will appear on the collection's status tracker (it looks like a little pie chart) at the bottom of your basket. Click this completed collection to get a key to open a new collection.
Note: You’ll be prompted to use the key to open a new collection right away, but you don’t have to—just click the “x” to cancel and save your key for later.
Use a Key
Sometimes, you will get extra keys for leveling up. If you have any keys in your inventory, they will show up at the bottom of your basket. Click a key to use it and open a new collection.
Different keys open different series. Bunny Keys come in different colors, and their color corresponds to the rarity of the collection it will unlock. For example, a white key unlocks a bountiful (white) collection, a red key unlocks a rare (red) collection, and so on. Turtle Keys are wildcards—they will open series of any rarity, (with the exception of some unusual series).
Buy a Key
Don't feel like waiting? You can buy a Turtle Key at any time to open a new collection. This will allow you to unlock a collection of any rarity whenever you would like! Turtle Keys can be found in the Marketplace under Boosts.