Chickens are highly diurnal creatures, meaning their daily activities are confined almost entirely to daylight hours. They possess extremely poor night vision, often described as functional blindness in low light. This lack of visual capability is why they exhibit a sudden cessation of movement and rush to roost as the sun begins to set.
Anatomy of the Chicken Eye
The chicken retina is specialized for daytime vision, but it is poorly equipped for perceiving the world after dusk. Like the human eye, it contains two types of photoreceptors: cones, which handle color perception and sharp detail in bright light, and rods, which manage vision in low-light conditions. Chickens have a cone-dominated retina, granting them tetrachromatic or even pentachromatic vision, allowing them to perceive colors and ultraviolet light invisible to humans. This specialization for daytime acuity comes at the expense of night vision, as the low rod count means the chicken’s eye lacks the necessary sensitivity to form discernible images when illumination is minimal.
The Critical Transition at Dusk
The inability to see in the dark is a rapid failure of the visual system as light levels drop below a certain threshold. Chickens instinctively seek their roosting spots during civil twilight, the phase just after sunset when the horizon is still clearly visible. They must navigate and secure their position while there is still enough light for their cone-dominated eyes to function effectively. Once ambient light falls further, moving into the nautical twilight phase, the visual system effectively shuts down, causing temporary blindness and forcing them to become completely immobile.
Nighttime Behavior and Safety
The necessity to remain motionless in the dark dictates nearly all of a chicken’s nighttime behavior. Chickens instinctively seek the highest possible perch before the light fades, a behavior rooted in their wild ancestry that offers safety from ground predators. Once settled on the roost, they enter an almost trance-like state, sitting on their feet and becoming highly unresponsive to external stimuli. This immobility is a survival strategy, as movement would make them an easier target for nocturnal predators such as raccoons, foxes, and owls. Since they cannot see to flee or defend themselves, their only defense is to remain still and unnoticed.
This extreme vulnerability means the security of their coop is paramount for any owner. Owners should always ensure chickens are locked into a secure, predator-proof structure before true darkness sets in. Trying to handle or move a chicken after sunset is straightforward because they are essentially blind and will not struggle, but this should be avoided unless absolutely necessary to prevent unnecessary distress. The use of automatic coop doors that close at dusk and open at dawn can provide a consistent and reliable safety measure, capitalizing on the chicken’s highly predictable diurnal nature.