Pecking at string by individually caged, adult laying hens; color preferences and their stability
Publication Type: |
Journal Article |
Year of Publication: |
1998 |
Authors: |
R. Bryan Jones, Nina L. Carmichael |
Publication/Journal: |
Applied Animal Behaviour Science |
Keywords: |
chickens, colour preferences, environmental enrichment, pecking behaviour, pecking devices, string |
Abstract:
Hitherto, relatively few studies have attempted to identify the influential features of devices intended to attract and sustain the interest of captive animals and to enrich their environment. In the first of a series of experiments intended to evaluate the attractive (peck-eliciting) properties of selected classes of stimuli and of variations in their component features, we found that young domestic chicks are strongly attracted to bunches of string. The present study focused on adult laying hens. In Experiment 1, we examined the responses of 45-week-old, individually caged laying hens to differently coloured (white, yellow, orange, blue) bunches of string when these were presented singly on consecutive days (Trial 1). This procedure was repeated at 51 weeks of age (Trial 2) in order to assess the stability of observed preferences. (Preference was defined as the tendency to orient more towards and to peck more at string of 1 particular colour than of the 3 other colours). The hens showed clear colour preferences. White or yellow bunches of string elicited more approach and were pecked significantly more readily and frequently than the orange or blue ones in both trials. In Experiment 2, we compared the pecking responses of previously untested hens when the 2 devices identified as the most (white) and the least (blue) attractive in Experiment 1 were presented simultaneously at each of 2 ages (80 and 86 weeks). Significantly more pecking was again directed at the white rather than the blue string in both trials. Though some birds shifted preference across trials, the collective stability of the observed preferences is demonstrated by the fact that similar findings were obtained in each of the two trials carried out at intervals of 6 weeks in each of the two experiments. It was concluded that bunches of string are attractive pecking stimuli for laying hens, that white or yellow bunches are preferred to blue or orange ones, that collectively the observed preferences are stable (though some birds shifted preference across trials), and that, despite the brevity of presentation, the birds showed no evidence of habituation upon repeated exposure (rather they pecked more at all the devices during the second trial than they did during the first). Continued studies in this area may guide the development of environmental enrichment procedures and/or devices intended to divert potentially injurious pecking away from other birds.