If you hatch your Frankenbunny with any other pet, you will have a chance of getting back that other pet, or another Frankenbunny. Either case, the baby will have a combination of traits from both of its parents.
There are personal hatching circle and that is how you would hatch 2 of your own pets. But if you would like to hatch i can hatch with you i've got an array of pets from you to chose from.