I have read that only the school pets obtained at level 48 can be used to make hybrid pets. The process can fail and leave you with another copy of the pet you used. Further they have to be mixed with other 48s, crown shop pets and pets bought for gold don't seem to make hybrids when mixed with a 48.
Non-48s don't seem to make hybrids at all. You just get another copy of the pet you used to make the egg. There are ten skills/abilities that each type of pet has a chance to learn. They only get four of each.
lets say I mix my imp with a friend's death leprechaun. Because the imp is mine, I will get an imp pet. His death leprechaun has the death dealer skill, but the hatch ling imp will never have a chance to learn it because the imp type cannot learn death dealer. The new imp would only be able to learn imp type skills. In short, neither of us get anything out of hatching our pets together. I would be better off buying another imp at the pet shop.
The hatchery got a bunch of publicity and hype. It is a bit anticlimactic that: there are only seven pets that can make hybrids, that you have nearly finished the game by the time you can get one of those pets, and mixing any other kind of pet just gives you another copy of what you already had.
I did read that if you use the hatchery the new pet may start as an ancient instead of a baby. That would make it easier to get to epic.
I know today i was so excited bacuse i fianlly got enough gold after a week, and i wanted to mix with orthrus. i was really hoping to het the ice hound but instead i got another collosus. i mean what am i supposed to do with a pet i already have :( adn to top it off i am now left with no gold and no pet. that i say is a huge issue :(
hmmm. After the next update, exclusive pets can be bred to make "something else." There is still a large chance that when you breed with an exclusive pet you will get another copy of the non exclusive participant. Apparently, if you use 2 pets on the exclusive list you are guaranteed to hatch "something else." One hopes it is cool "something else" and not a stray piggle. It would seem that a pet of mixed ancestry will be able to inherit skills from it's parents. It could look like one parent but get to have talents and powers from the other parent's type or from both parent's types.
I would advise against using the hatchery even after the next update though. There are bound to be severe bugs related to this "something else," I would feel more comfortable waiting until the update after this one. On the other hand I have not pets on the exclusive list so I won't be doing anything anyway.