Updated lists:
CATGUT:
#3 Joel Grey: she plays in the band in Joel's first number "Wilkommen"
#6 Jim Nabors: she's one of the chorus animals in Jim's closing number "Thank God, I'm a Country Boy"
#16 Avery Schrieber: she sings with Rowlf, Baskerville and Muppy in the UK Spot "May You Always"
#21 Twiggy: she appears in the bedroom after “The King’s Breakfast” ends
#32 Steve Martin: she appears in the audience at the beginning of the show
#35 Dom DeLuise: she appears in the audience throughout the show
#51 Roy Clark: she dances with the Afghan Hound in "At the Barn Dance"
#77 Victor Borge: she appears briefly in "Rock Around the Clock"
#97 Gene Kelly: she makes a cameo appearance as an eskimo in the opening number "On the Bayou"
ROVER JOE:
#23 Kaye Ballard: he appears in the UK Spot "Life Gets Tedious"
#76 Dyan Cannon: he appears in the opening number "Hound Dog", in the UK Spot "Old Dog Trey" and in Dyan's closing number "Hey There, Big Spender"
#119 Linda Ronstadt: he appears in the man who was driving way out west in "The Cat Came Back"
T.R. ROOSTER:
#10 Harvey Korman: he leads the procession of marching chickens and appears in the goodnights
#21 Twiggy: he appears in the bedroom after “The King’s Breakfast” ends
#28 Rich Little: he appears in the audience after Gonzo's dancing chicken act ends
#31 Edgar Bergen: he conducts the singing chickens in the opening number "Baby Face" and appears in the audience at the end of the number
#32 Steve Martin: he appears in the audience at the beginning of the show
#39 Lou Rawls: he dances with Flo the Chicken in "At the Dance"
#44 Petula Clark: he plays the white-hat hero in the chicken saloon sketch
#51 Roy Clark: he dances with a chicken in "At the Barn Dance", sings in Roy's closing number "Sally Was a Good Ol' Girl" and appears in the goodnights
#66 Leslie Uggams: he appears briefly in the background when Camilla dances in the third backstage scene
#69 Roger Miller: he sings and plays a guitar in Roger's closing number
#100 Shirley Bassey: he appears in the opening number "Boogie in the Barnyard"
#117 Johnny Cash: he appears in the background in "Ghost Riders in the Sky"
#120 Roger Moore: he appears in the opening number "In the Navy"