Licht-im-Terrarium: Literaturdatenbank

The light we see affects our mind and a wide variety of metabolic processes within our body. Eyes are undeniably one of our most important
organs. It is where light penetrates the retina and stimulates multiple biological functions. The light we perceive is part of the electromagnetic spectrum our eyes can detect, known as the visible spectrum.

The same is true in animals, including poultry, but with one significant
difference. The spectral sensitivity and visible spectrum of poultry, or what they actually see, is not the same as humans. It is why chickens or turkeys may behave differently under the same intensity light from two different sources that look identical to us. Chickens and turkeys absorb light through their eyes in ways humans don’t. In addition to retinal light perception, poultry can sense light through the pineal gland commonly called the “third eye” situated on the dorsal surface of the brain. The avian pineal gland is particularly involved in the control of circadian rhythms and sexual activity. A circadian rhythm is a 24-hour cycle in the biochemical, physiological or behavioral processes of all animals.