Connecting Chicken Cognition And Welfare
Adult chickens have cognitive capabilities comparable to those of mammals, including episodic memory, transitive inference, and self-control. However, little is known about how chicken cognition develops and is challenged on commercial farms, where most of them are kept. Understanding chicken cognition could provide fresh perspectives on the causes and mechanisms behind many common chicken health and welfare problems. Applied research to solve chicken welfare issues could also become more impactful if we understand how cognition and welfare are interconnected.
A recent scientific review highlighted three main advantages of studying chicken cognition:
- It can help industry professionals improve their environmental and husbandry practices to better support chickens.
- It can improve chicken welfare problems.
- It can inform how we measure chicken welfare.
Recently, a group of researchers explored how learning more about chicken cognition could help address three widespread welfare issues occurring on farms worldwide. These include the issue of uneven range use by the chickens — where some individuals spend loads of time outdoors and others barely leave the barn despite ample opportunities to do so; the serious issue of injurious feather pecking in laying hens; and the unfulfilled behavioral and physiological needs in so-called “broiler breeder” birds. While various internal and external factors may play a key role in the first two welfare issues, broiler breeders’ unfulfilled needs are mainly linked to the strict feed restriction these animals are subjected to.
The Curious Case Of Uneven Range Use
“Free-range” systems are becoming more popular around the world, where chickens have access to outdoor ranges to fulfill natural behaviors like dust bathing and foraging. Besides the rewarding nature of being outside, range use is also associated with a reduced risk of plumage damage and feather pecking among chickens. However, not all chickens use the outdoor spaces equally, which can lead to barn overcrowding and subsequent health and behavioral problems. External factors surely play a role in range use, as more chickens seem to prefer the outdoors in summer and during the day than in winter and in the evening. Similarly, research suggests that the more tree cover there is around a given range, the higher its use is. In terms of individual differences, males, older individuals, and flocks of mixed or non-white genotypes were seen to explore the range more, which may have something to do with fearfulness among white hens.
Recently, studies have inspected how intrinsic factors such as fearfulness and exploratory behaviors relate to range use. Several studies show that the level of exploratory behavior can be associated with an individual’s cognitive abilities. This is where chicken cognitive research can come in handy. For example, it may turn out that certain individuals desire more outdoor time than others, which can improve rearing practices.
There seems to be more to learn on this topic, as the data acquired thus far is contradictory: while some studies point to high-rangers being more sociable, others support increased sociability in low-ranging chickens. Similarly, there are conflicting results when comparing free-range broiler chicken and layer hen preferences. While the use of physical enrichment for laying hens, for instance, might successfully stimulate their spatial cognition, the opposite may occur for broiler chickens, with limited or even negative impact on range use. The relationship between cognition and range use is highly complex and needs further investigation.
The Grim Topic Of Pecking
Chickens naturally engage in pecking when foraging and dustbathing. However, in the animal agriculture industry, chickens often start pecking each other. This is especially common among laying hens. If pecking becomes frequent, it can lead to severe feather loss, injury, cannibalism, and death. In fact, when cannibalism occurs as a result of pecking, up to 30% of hens in a flock may die.
There is a relationship between foraging behavior and feather pecking, where chicks that forage more tend to peck others more in adulthood. There is a theory that harmful feather pecking manifests as a redirected foraging behavior. Painful beak trimming is often used to curb pecking behavior, but this is extremely harmful for the animals’ welfare.
There are significant individual differences when it comes to the intensity of feather pecking. High-pecking hens are shown to develop routine-like behaviors when facing stress and are mainly guided by internal mechanisms, while low-pecking individuals tend to be more flexible and instead react strongly to their environment. Different forms of stress at different life stages (e.g., maternal stress, early and late-life stress), is seen as the main predictor for pecking behavior. That being said, many fundamental questions related to this issue and core causes behind it remain mostly unanswered.
One question is how feather pecking is transmitted socially. Researchers suggest that several on-farm animal management strategies, such as the use of visual barriers, removing high-pecking individuals, or adding trained demonstrator hens, could potentially address the problem. The authors suggest that research on social cognition may play an important role in understanding the links among feather peckers, non-feather peckers, and the victims of this harmful behavior.
The Unfulfilling Lives Of Broiler Breeder Chickens
To maintain industry-acceptable levels of health and reproduction, birds used to breed broiler chickens often have their feed severely restricted. The amount of feed provided can be reduced by as much as 90% to counteract their growth. Although beneficial in preventing health problems and poor welfare due to illness, the animals are frequently reported to be chronically hungry, frustrated, and sexually aggressive or dysfunctional.
Recent studies indicate that cover panels, bales of wood shavings, and materials for foraging and dust-bathing might reduce aggression and stereotypies — in other words, repetitive, pointless movements indicative of high-stress levels. However, such studies are few and far between. More research is needed on the negative impact of chronic hunger on chicken cognition. Undernutrition and long periods of food deprivation are known to have impairing effects on brain development for multiple species, thus the birds in these systems may be at risk of reduced cognitive abilities.
How chickens learn, interact, and react to their physical and social environment is key to gauging their individual needs and on-farm welfare. Because of this, the authors call for action — we need to make the scientific community, the general public, and policymakers aware of this knowledge gap. Animal advocates can play a role in bringing attention to the lack of chicken cognition and welfare research in existence. As the public demands improved welfare practices for chickens used in the agriculture industry, it’s important that welfare demands rely on high-quality information that includes cognitive factors.