Happy Pets: Albinos and Dinos stuck in Trapped Pet's Kennel
Among the rewards are albino pets and dinosaurs. According to the Facebook fanpage, "You have the chance to get 1 of 6 exclusive pets (pet is based on rarity)!"
You won't be able to release your pets alone, meaning you'll need your friends to help you with the locks. So start sending out those help requests so you can add a new rare pet to your collection of animals.