So Bob the Turkle did not change very much from the concept art I have seen. In the concept art, his beard is a little shorter. My guess is they found it gave the creature more life-like and grounded to have the beard obscure some of the body which is why its longer in the final film version. The puppet also has some more hair on the lower neck which the concept art does not show.
During the conceptual phase he’s a smoker and has a pipe. That’s right. Apparently by the time he got on set, he kicked the habit. He could be on the patch, I can’t be sure. But Bob the Turkle is proof you can kick the habit.
The creature in the top box on Bob’s back is obscured in the video above. The concept art shows creatures with purple bodies, almost like chicken bodies with no feathers, no legs or wings, long necks and snouts. The second box to the top has a creature very close to a frog dog. In the concept art it is more ready to attack than it is in the video we’ve seen, with its arms set to obscure the puppeteer’s head. The next to bottom box has the same space birds we see in the video above. However, the bottom of the cage contains a space rat! It even has a mechanism designed to make the rat’s tail wag when he walks.
The concept art also shows how the puppeteer will fit inside!
The puppeteer’s head is inside the frog dog location (second box to the top). The puppeteer’s right arm is inside one of the space bird’s heads. The left arm of the puppeteer is attached to a rod that goes inside the puppet’s head and allows him to control the neck and head movement. The puppeteers feet go into the actual feet of Bob the Turkle.
The rat in the bottom cage has a note “Tail Twitches,” “Motor Driven,” “or connected to performer.” The top tier creatures has a mechanism drawn up that allows the creatures in the top to have their heads move up and down.
It is signed “Joe,” “13-8-13.” I honestly can’t make out the last name of the artist.