The Giant Chicken was likely intended to be a boss in the 2011 puzzle video game Portal 2. It would have been a giant chicken loose in Aperture Laboratories that would have presumably tried to kill the player character.
Biography[]
The Giant Chicken is among the most enigmatic and mysterious pieces of cut content from the Portal series. Next to nothing is known about its origins, role in the story, development, or so forth. It is speculated from the concept art that it would have been a boss in early stages of the game, being fought in an abandoned office area. It would have most likely been a past Aperture Science test subject still on the loose.
There is also speculation that the chicken may have been intended to appear in a Portal prequel, though there is little evidence to support this.
Despite not being featured in the game, evidence of the chicken's leftover files are in the "scripts" folder of Portal 2's directory files.
The Giant Chicken eventually made a cameo appearance in the game Aperture Desk Job.