In the player garrisons coming in Warlords of Draenor, one of the medium-size construction options is the Pet Stable. While we were all initially uncertain as to its purpose, more has since been revealed. Below is an explanation from Cory Stockton's Twitter account.
Do note that he specified current plan. The expansion has just been announced. Many things will change before any beta phase. Even more will change before launch.
Filed under: BlizzCon