Angry Chicken was originally simply a 1/1 with no special ability, intended to be "kind of a joke", and "something for everyone to latch on to as "the worst card"".[1] The Enrage was suggested by Quality Assurance "homie" Jeff Manners.[1]
The Enrage effect might be a reference to the Legend of Zelda franchise, where Cucco are completely harmless until you beat them several times, which then causes them to become invulnerable and attack you relentlessly until you leave the area or die.
This card inspired the Hearthstone podcast The Angry Chicken. Following the podcast's success, Ben Brode planned to alter the art for the card in order to provide some "truly angry chicken art" in tribute to the podcast, but changed his mind after deciding a change to established art would be too confusing for players, choosing to instead commission some "especially angry" art for the Gnomish Experimenter's Chicken.[2]
Interestingly in light of the above, the full art of the Angry Chicken appears to be displaying the end result of the Gnomish Experimenter causing the player to draw a minion card. It seems clear the chicken has been transformed into a chicken from some kind of humanoid, given the now-empty suit of armor that seems to have fallen to pieces around it, meaning that the art would be ideal for the Experimenter's Chicken, and the Experimenter's Chicken ideal for the Angry Chicken.
Flavor text now reads: "There is no beast more frightening (or ridiculous) than a fully enraged chicken." (previously: "There is no beast more frightning (or ridiculous) than an fully enraged chicken.").
Flavor text now reads: "There is no beast more frightning (or ridiculous) than an fully enraged chicken." (previously: "He wasn't always angry, but eventually all chickens learn that they are destined to be dinner.").