"On the other hand, an animal that can anticipate an event might benefit from cues to aid prediction, but may also be capable of expectations rendering it vulnerable to thwarting, frustration and pre-emptive anxiety."
She added, "The types of mental ability the animal possesses therefore dictate how they should best be managed and what we might be able to do to minimize psychological stress."
Abeyesinghe, a member of the Biophysics Group at Silsoe Research Institute in England, and her colleagues tested hens with colored buttons. When the birds pecked on one of the buttons, they received a food reward.
If the chicken waited two to three seconds, it received a small amount of food. If the bird held out for 22 seconds, it received a "jackpot" that paid out with much more to eat.
The study is published in the current
Animal Behavior.
"In their natural environment it may pay to get food while you can, before someone else does," Abeyesinghe told Animal Planet News. "But counter to this, we found that when a much larger food reward was delivered for the jackpot condition, hens chose it over 90 percent of the time, ruling out that they have absolutely no awareness of the near future."
Prior studies have found that neuron organization in chicken brains is highly structured and suggests that, like humans, chickens evolved an impressive level of intelligence to help improve their survival.
Unlike humans, the chicken brain has a remarkable capacity to repair itself fully after trauma, which has puzzled neuroscientists for years.
It remains unclear what exactly goes on in the minds of chickens, which are raised at a rate of 40 billion birds per year to satisfy human consumption demands. Abeyesinghe, however, did say, "They probably show more cognitive ability than people would generally credit them with."
Raf Freire, a lecturer in the Centre for Neuroscience and Animal Behavior at the School of Biological, Biomedical and Molecular Sciences in the University of New England, Australia, agrees, but already suspected that animals and birds, particularly chickens, had higher levels of intelligence than currently thought.
"An ability to show self-control improves an animal's survival in their natural environment and would be expected to have been selected by evolutionary processes," Freire told Animal Planet News. "Hence, it did not surprise me that chickens show self-control."
He added, "What is astonishing, however, is that the researchers were able to so elegantly and convincingly demonstrate this in chickens."
Both Freire and Abeyesinghe hope the findings will lead to more humane treatment of birds and animals raised for slaughter. Aside from animal rights issues, other research has indicated that if a bird or animal feels stress before killing, that anxiety may adversely affect the quality, taste and texture of meats.
