The Beaker: May 2014

Head and feather pecking behaviour in turkeys can escalate to severe pecking and cannibalism under commercial conditions, creating a significant welfare concern and economic loss. What causes this type of pecking, and what can be done to reduce its incidence?

In a review published in the World’s Poultry Science Journal* in December 2013, authors Hillary A. Dalton, Benjamin J. Wood and Stephanie Torrey examined the different types of injurious pecking in turkeys and the factors that may contribute to the behaviour, including environment, genetics and nutrition.

Injurious pecking can be differentiated as three distinct behaviours in turkeys. Head, neck or snood pecking is described as a form of aggression is often used to retain dominance and typically follows a social disturbance. Feather pecking occurs on many different levels, from gentle to more forceful repeated pecking or plucking of feathers on the back, wings and tail of another bird. In its gentlest form, feather pecking is considered as a form of social preening or investigatory behaviour; escalating to more severe feather pecking that involves loss and consumption of plumage and escape behaviour by the victim. If bleeding occurs as a result of feather pecking, the most severe behaviour of cannibalism
often follows.

All three levels of injurious pecking behaviour result in animal welfare and production efficiency issues. While there is no consensus on the cause, injurious pecking behaviour may possibly be traced to a mismatch of the needs of young turkeys to the conditions supplied in a commercial environment. For example, it is possible that the fluorescent or incandescent lighting typically used in commercial settings may distort the appearance of emerging feathers and initiate investigatory pecking.

Toms are more likely than hens to exhibit head pecking behaviour, becoming more aggressive following sexual maturity. In the wild, young birds will head peck as a precursor to developing the skills required by mature birds to establish the “pecking order” in the flock. If this behaviour is learned, is it possible that isolating those individuals with a pecking propensity could help prevent the spread of this behaviour through the flock?

The need to peck is shaped by genetics, environment and nutrition. Current research in turkeys considers head pecking as an act of aggression but it can also represent re-directed foraging behaviour. A lack of environmental stimuli may be a motivator although some research has shown that birds still peck other birds even if foraging material is made available.

Farm management practices that may heighten stress on the birds, such as poor ventilation, inappropriate humidity,
temperature extremes, flies or parasites, high stocking densities, inappropriate lighting, management changes or foot problems may contribute to injurious pecking.

Interestingly, unlike other forms of injurious pecking, the rate of aggressive head pecking in turkeys is affected by familiarity of the birds. Male turkeys will peck unfamiliar individuals in a group as small as four birds.

The presence of numerous confounding variables has prevented meaningful insight into the relationship between genetics and injurious pecking. Has selection for larger, faster-growing birds unintentionally selected for higher rates of aggression? When exposed to similar environments, traditional lines displayed fewer injuries than modern lines, but it is difficult to specifically pinpoint the traits involved.

Pecking behaviour may also arise as a result of a nutritionally unsuitable diet or inappropriate feed form. Studies have shown that turkeys fed a crumble or mash diet versus pelleted, with higher fibre, and provided free choice instead of restricted, spend more time foraging and less time feather pecking.

Beak trimming with infrared lasers immediately following hatching is the current practice used to reduce injurious pecking. While preferable to hot-blade beak trimming, there are still concerns about the procedure being performed without analgesia. It is also possible that beak trimming increases the incidence of feather pecking by increasing frustration in the bird’s physical inability to grasp the feathers.

Lower light intensity is often employed to reduce injurious pecking but it may also lead to eye abnormalities and musculoskeletal disorders; reduced lighting also hinders the detection of injured or lame birds. Removing the snood from toms, another common procedure, can also lead to chronic pain if not done correctly.

As stated in the World’s Poultry Science journal article, “Concern over trading one welfare concern for another has fostered interest in developing less drastic alternatives, such as genetic selection for gentler birds, environmental enrichment, and changes to diet, to reduce injurious pecking in turkeys…With this information it should be possible to design strategies to reduce injurious pecking, to lead to improvements in both welfare and production.”

The researchers are supported through the Canadian Poultry Research Council, Poultry Industry Council, Hybrid Turkeys and Agriculture and Agri-Food Canada.

*Dalton, H.A., B.J. Wood and S. Torrey. 2013. Injurious pecking in domestic turkeys: development, causes, and potential solutions. World’s Poult. Sci. J. 69:865-876