Swine have a panoramic field of vision of around 330°, giving them excellent awareness of their surroundings. They rely heavily on monocular vision (one eye at a time), which helps detect motion and potential threats. However, their binocular vision is limited, meaning pigs cannot accurately perceive depth or judge distances as well as humans.

This visual limitation has practical implications in barn design and lighting placement:

Uniform illumination across aisles and pens helps pigs navigate safely.

Avoiding glare or sudden brightness changes prevents fear responses or hesitation during movement.

Good lighting therefore improves not only welfare but also handling efficiency and animal safety.

The visible light spectrum—the portion of electromagnetic radiation perceived as light—differs between species. While humans perceive wavelengths roughly between 380 nm and 780 nm, pigs’ visible range is narrower, from approximately 380 to 694 nm, with peak sensitivities at 439 nm (blue) and 556 nm (green).

This means pigs are less sensitive to red light and respond best to blue-green wavelengths. Lighting that takes this into account can better support pigs’ natural biological rhythms and behaviour.

Types of Spectral Sensitivity:

1. Cone Sensitivity: Determined by the types of cones and rods in the retina. Pigs are dichromatic, meaning they have two types of color receptors.

2. Behavioral Sensitivity: Relates to how pigs respond to light in their environment — more relevant for welfare and productivity.

3. Research shows that light spectrum, intensity, and photoperiod all interact to influence hormonal regulation, particularly melatonin and reproductive hormones, which in turn affect growth rate, fertility, and stress levels.

Adapting light to pigs’ visual and behavioral needs offers multiple measurable benefits:

Improved vision and spatial awareness – Pigs move more confidently, reducing falls and injury.

Enhanced reproductive performance – Proper light exposure supports estrus detection and fertility in sows.

Better feeding behavior – Pigs under stable light conditions show increased feed intake and improved growth rates.

Reduced stress and aggression – Calmer herds with fewer fights or dominance displays.

Stronger immune function – Consistent circadian rhythm contributes to overall resilience.

Lighting should not be viewed as mere visibility — it’s a biological control tool that directly influences animal welfare and farm economics.