I have stared at a chicken's eyes and seen and felt this stupidity Herzog is talking about...
Werner Herzog on Chickens from Tom Streithorst on Vimeo.
Chicken stupidity is so profound it's philosophical.
I've also seen a chicken run about without its head—legs, feathers, blood spurting from where the head should be. It ran perfectly well without its head. It even ran across a narrow bridge that was in my cousin's backyard. Only a fence stopped the headless bird.