Feather pecking in poultry: the application of science in a search for practical solutions

Traditional battery cages for laying hens will soon be banned in the EU but the increased risk of feather pecking (FP) hampers the adoption of alternative housing systems. FP can cause injury and lead to cannibalism and the painful death of target birds. Current management practices (beak trimming, low light) have associated problems. In a joint European project we sought alternative solutions. In our study of associated traits, birds from a line showing low (LFP) rather than high feather pecking (HFP) exhibited greater sociality (motivation to be near companions) and a passive ‘coping’ style. High sociality and passivity were also negatively associated with FP in adults. These findings may guide future breeding programs. Trimming hens’ feathers to mimic the results of FP elicited pecking and some cannibalism, even by birds that had previously shown no FP. Social transmission of gentle but not severe FP occurred when LFP and HFP birds were housed together. Gentle pecking could conceivably lead to severe FP. We then examined chickens’ pecking preferences to guide environmental enrichment strategies. Bunches of string elicited substantially greater interest than other stimuli, including feathers, and white or yellow string was the most attractive. The birds’ manipulation of the string resembled preening. Incorporating silver beads or moving the devices reduced pecking. String sustained lengthy interest, reduced FP in HFP birds, and decreased feather damage in caged layers on a commercial farm. String offers effective, affordable and practicable environmental enrichment. The integrated application of appropriate environmental and genetic strategies is likely to attenuate the expression of FP and its harmful consequences.

Pecking preferences and pre-dispositions in domestic chicks: implications for the development of environmental enrichment devices

Environmental enrichment is thought likely to benefit chickens and farmers in many ways; these include reduced fearfulness and feather pecking and improved productivity. Enrichment devices would intuitively be more effective if they reliably attracted and sustained appreciable interest but many fail to do so. This may reflect the fact that the choice of stimuli often reflects availability and human preconceptions rather than a critical consideration of the birds' preferences and pre-dispositions. We had previously identified string as a particularly attractive pecking stimulus for chicks and adult hens (Gallus gallus domesticus) of a laying strain (ISA Brown). In the present study we found that chicks of another laying strain (Lohmann Brown) also pecked sooner and more at a bunch of string than at chains or beads (Experiment 1). White or yellow strings were preferred to red, green or blue ones (Experiment 2) and white string elicited more pecking than did combinations of white and yellow or of all five colours (Experiment 3). Varying the length and width of the bunches of string exerted no detectable effects on pecking (Experiment 4) whereas incorporating small, shiny beads in the white string devices actually reduced pecking (Experiment 5). Virtually all the devices elicited progressively more interest with repeated presentation; this trend was particularly marked for white string. Collectively, the present findings demonstrate that young domestic chicks have clear and specific pecking preferences. Although the magnitude of response varied across experiments, white string consistently elicited the most interest. Our two main conclusions are: (i) white or yellow strings were particularly attractive stimuli that drew increasing interest, at least in the short term, and (ii) simple devices were preferred to more complex ones, or at least to those used here.

Can ‘Environmental Enrichment’ Affect Domestic Chickens’ Preferences for One Half of an Otherwise Symmetrical Home Cage?

Chickens were reared in pairs in wooden boxes from 1 to 10 days of age. One chick from each pair was marked to facilitate identification and its position in one or other of the symmetrical halves of the home box was noted at each of 32 visual scans carried out every day. Cumulative sightings in each half were calculated across the first 5 days to establish the least preferred half. Three ‘enrichment’ objects were then placed in the least preferred half of each box on day 6. The chicks ‘positions were again recorded at each of 32 scans on 5 consecutive days. The enrichment objects were avoided on day 6 but such neophobia waned within 24h and a weak, non-significant trend for enrichment to increase usage of the least preferred half became apparent. The strong side preferences shown by the chicks before the introduction of enrichment stimuli, and their transitory neophobia, sound important cautionary notes for the design and assessment of husbandry and environmental enrichment procedures.