Chickens have been a part of the Muppet world since 1972, when the first group of Muppet chickens was created for the Tales From Muppetland special The Muppet Musicians of Bremen. They were precursors to the chickens from The Muppet Show, except they had slightly different eyes. T.R., one of the main characters, would later appear on The Muppet Show as well.
The Bremen chickens were used during the first and second seasons of The Muppet Show. In one episode, guest starring Rich Little, a bunch of real chickens were featured, auditioning forGonzo's dancing chicken act. It was in this episode that Gonzo developed his obsession with chickens.
During the third season, some new chickens were built with more defined eyes. One of the chickens got the name Camilla and became Gonzo's girlfriend. (Although even Gonzo doesn't know which chicken is Camilla sometimes; they all look alike.)
A black rooster was added to the Muppet Show cast during the second season, and a little chick during the third season. In one of the first episodes, guest starring Harvey Korman, a chicken suit was made for the guest star; it would later be used occasionally whenever a huge full-body chicken character was needed.
The white Muppet chickens made a few rare appearances onSesame Street; sometime during the 1980's, a group of brown chickens were added to the Sesame cast, as well as a brown/black rooster. The main difference, aside from their color, from their Muppet Show counterparts is their rounded eyes and sharper beaks.
Other notable Muppet chickens are the Giant Man-Eating Chickenfrom John Denver and the Muppets: A Rocky Mountain Holiday, and the Humongous Chicken from The Adventures of Elmo in Grouchland. The latter was a white chicken with a much smaller head and big, round eyes, but no eyelids. A slightly altered version (donning feminine eyelids) made several subsequent appearances on Sesame Street; one incarnation being Super Chicken. The puppet was later recycled as many more characters on 'Sesamstrasse.
The Muppet chickens usually communicate with squawks, although they are known to speak at times.
The Muppet chicken, owned by Telly, got a small part in a 4D movie. After this the chicken moved to The Netherlands and got his own part in Sesamstraat. The chicken listens to the name Stuntkipand is a daredevil. Another international chicken is actually a rooster named Kareem from the Israeli/Palestinian co-production.
The chickens are built without an eye mechanism. Instead, the Muppet builders found an alternative by giving some chickens one wide open eye and one 'relaxed' eye with eyelid; this way, the chicken could change emotions by quickly turning its head.