The Clucker appears to be a mechanical chicken with a white body, red wattle and tail feathers and a yellow beak. It has an audio antenna on either side of its head and its eyes are perpetually frowning.
Cluckers are often used to operate gun turrets aboard some of Dr. Eggman's airships. The robots are completely immobile as they are installed directly into the gun emplacements. The turrets they operate fire shells that resemble chicken eggs.
Sonic the Hedgehog 2
In their debut appearance, Cluckers appeared on board Dr. Eggman's Wing Fortress. They would remain hidden inside turret domes until the player entered their range, at which point the Clucker would emerge and start firing egg shells in the direction that the player came from. The Clucker could be destroyed with a Spin Jump, though if the player jumped over the Clucker, it would still face whichever direction the player had come from originally and could not turn around.
Sonic the Hedgehog 4: Episode II
Cluckers appear in Sky Fortress Act 2 and their appearance has only been slightly modified since their debut. As well as having a few visible seams, their tail feathers are now white and they fire regular grey cannon balls from their guns rather than white egg shells. Cluckers are normally found in stationary turrets along the decks of the Sky Fortress, but can also be found on hovering platforms.
Sonic Lost World
Cluckers reappear in both the Wii U and Nintendo 3DS version of Sonic Lost World. During the game, all the Badniks, the Cluckers included, got hijacked by the Deadly Six. In this game, Cluckers appear in multiple Zones and have their cartoon-like look from Sonic the Hedgehog 2. Regular Cluckers appear in Silent Forest Zone 1 and Lava Mountain Zone 3, where they pop out of their turret and shoot egg-shaped projectiles at Sonic. If Sonic gets too close to a Clucker, it will withdraw into its turret dome and cannot be attacked.
In some cases, the Cluckers appear on Grind Rails where they ride minecarts while shooting at Sonic. In the Wii U version of Tropical Coast Zone 3, there are Cluckers controlling bulky, spider-based vehicles from where they regularly shoot projectiles. If the player tries to circulate from the top, the vehicle will land on the above pathway with the spiked armour on the cockpit, while the Clucker is hiding inside the vehicle. For all their different roles though, the Cluckers are easily beaten with a Homing Attack.
Returning to their original design from Sonic the Hedgehog 2, Cluckers appear in the Flying Battery Zone. They are found in various outside sections of the ship, emerging from turret hatches and firing egg projectiles. This time, however, the Clucker can turn around if the player gets behind it and continue firing at the player.
Sonic the Comic
Clucker makes only a single appearance in Sonic the Comic. In the Issue #6 Sonic story "Attack on the Death Egg", Sonic and Tails board Robotnik's abandoned Wing Fortress to hijack its space shuttle in order to reach the Death Egg. While aboard the Wing Fortress, Sonic runs into a Clucker which opens fire on him, but Sonic easily avoids the attack and progresses through the enormous vessel.