I had a request on my youtube channel for more detail on how the mechanics of the first chicken in "Poultry in Motion" works, Since I cannot replay in Youtube with a picture posting I have described it here and put a link in the youtube comment section.
Here are a couple of photos taken from the rear to show how it works.
The 1/4" dowel that drops down from the chicken above has a 1-1/2" disc fastened to the end. The two cams on the shaft are the same size and positioned directly opposed (180 degrees) from each other, As each comes in contact with the disk it imparts a spinning motion to it. Since they are on opposite sides they cause the disc to move in the opposing directions. The pin protruding out of the back moves back and forth but the rotation is limited by the two pins sticking down from above. Without these pins the chicken would tend to drift in either direction to far.
There you go!
Automata is a creative blend of my life interests , engineering, art and woodworking.