The Determinist Explanation

Because of the autonomic responses of the chicken's internal nervous system in response to visual, auditory, and other sensory stimuli, moving through a complex neural network to stimulate the chicken's behavior. Likely, the neural programming within the chicken's brain was influenced by both pleasure and pain induction, perhaps modeled after previous experience such as when the chicken had previously crossed other roads and located a source of food, or an instinctual response left over from hundreds of thousands of generations of successfully-breeding ancestors which "hard-wires" into the unconscious motive imperatives of the chicken the notion that across the road, a place of apparent safety from foxes or other threatening predators is likely to be found, e.g., a coop. While our understanding of the natural phenomena which are the inputs leading to the particular behavior under examination is admittedly limited, a complete and comprehensive understanding of those phenomena and how they are internally processed by the subject is ultimately unnecessary to come to the realization that in no event can the chicken be understood to have "chosen" to have done this.