The Chicken quest (CLUCK!) can now be picked up by Horde players as well, via spamming /chicken at chickens around the world. While Alliance players buy the Special Chicken Feed needed for the quest from Westfall, the Horde can now buy the feed from "Westfall" William Saldean in Brill. Technically the Horde had access to this pet before, but it was a real pain. You had to wait around for an Alliance player to do the quest, then steal their egg off of the ground before they could loot it. Harsh. Now you can do it on your own, in your own town.
The Sprite Darter quest is still exclusive to the Alliance, but there's another way for the Horde to get their hands on it now: Killing the Sprite Darters of Feralas. We don't know how low the drop rate is yet, but it's safe to say that the Horde is going to drive the Sprite Darters to extinction. Alliance players, note that you cannot kill these Darters. We still have to do the quest(s).
See? Blizzard loves you, too. They love all of us equally. ...Usually.