What's in a peck? Using fixed action pattern morphology to identify the motivational basis of abnormal feather-pecking behaviour

Abstract

Like many captive animals, hens, Gallus gallus, used for agricultural production perform abnormal behaviours. They are particularly prone to feather pecking, the severest form of which involves the pecking at and removal of feathers, which can cause bleeding and even stimulate cannibalism. The two main hypothesized explanations for feather pecking concern frustrated motivations to forage or, alternatively, to dustbathe, leading to redirected behaviour in the form of pecks at plumage. Previous work on pigeons has shown that the detailed morphology of pecks involved in drinking and feeding, or in working for food or water, involves motivationally distinct 'fixed action patterns'. We therefore used methods similar to these fixed action pattern studies to quantify the motor patterns involved in foraging and in dustbathing pecks, for comparison to feather pecking. We videoed 60 chickens pecking at a variety of forages and dustbaths, along with novel objects, water and bird models that could be feather pecked. We recorded the durations of the head fixation before the peck, between the head fixation to beak contact with each stimulus and of the whole peck sequence. We used mixed models to assess whether the motivation underlying a peck affected its morphology and whether severe feather pecks resembled or differed from either dustbath or foraging pecks (or even novel-object pecking or drinking). The motor patterns involved in pecks at forages, dustbaths, novel objects and water all varied significantly; importantly, the motor patterns involved in pecking during dustbathing and foraging differed (P < 0.0001 for all measures). Severe feather pecks proved similar to foraging pecks (NSD: power > 0.95) but different from all other pecks, including dustbathing (P < 0.0001 for all measures). These results indicate that severe feather pecking derives from frustrated motivations to forage, not to dustbathe. More broadly, they suggest that finely analysing fixed action pattern morphology can help elucidate the motivational bases of puzzling abnormal behaviours in captive animals.

Welfare improvement in laying hens during the hot period under a semi-open rearing system through dietary arginine and vitamin C supplementation

“…The blood corticosterone, glucose and triglycerides were lower than respective levels in controls. Olsson & Keeling (2005) and Dixon et al (2008) found that the behaviour of taking dust baths is an important indicator of social welfare of birds. According to Sherwin & Kelland (1998), the higher welfare in turkeys increased the time spent in stretching, feather pecking, and dust bathing.…”

Logistic regression to estimate the welfare of broiler breeders in relation to environmental and behavioral variables

“…DIXON et al (2008) noted that the behavior of feather pecking of severe way is associated to motivational frustrations about scratching, and not about the dustbath, as reported by SHIELDS et al (2004), because the morphology of feather pecking is closer to foraging, unlike the morphology of taking a dustbath and of cleaning the feathers.…”

“…GRAVES (1982) stated that behavior is a window of the body for the outside, enabling better estimate with precision the welfare of birds. OLSSON et al (2005) and DIXON et al (2008) found that the behavior of taking the dust bath is an important indicator of social welfare of the group, and this behavior is mainly affected by the bedding material (JONG et al, 2007). ZIMMERMAN et al (2006) observed that different sizes of groups provide significant differences in the expressions of aggressive behavior.…”

The association between plumage damage and feather-eating in free-range laying hens

“…De Haas et al (2010) deduced that high featherpecking birds have a stronger pecking motivation than low feather-pecking birds, rather than a preference for eating feathers. Newberry et al (2007) also found that birds which performed more SFP performed more ground-pecking during rearing, and Dixon et al (2008) deduced that birds with a high foraging motivation can be more likely to perform SFP if foraging behaviour is inhibited. Kjaer (2009) suggested a hyperactivity model for SFP, whereby birds that perform more SFP have higher general activity levels.…”