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Feather pecking: solutions through understanding

Contract nr: FAIR-CT97-3576
Project nr: 3576
Project type: SC
Starting date: 01/01/1998
Duration: 42 months
Total cost: 923,000 EUR
EC Contribution: 575,000 EUR
Scientific Officer: Lucia PENA ALBERDI
Research topic: Animal welfare

Egg production represents an important sector of the farming industry. Approximately 250 million laying hens are kept in the EU. Because of public concern over poultry welfare, the demand for non-caged eggs and, consequently, the development of alternative housing systems has increased, particularly in Northern Europe. However, the introduction of alternative housing systems produces an increased risk of feather pecking (FP). FP is widely considered to be one of the major welfare problems facing laying hens, particularly if they are housed in alternative systems rather than battery cages. FP has many detrimental effects. FP consists of pecking and pulling at the feathers of other birds and thereby causing damage to the plumage and loss of feathers. This can impose a financial burden on the industry because birds with few feathers lose heat faster, have greater energetic needs and thereby cost more to feed. Not only can birds be injured when they are severely pecked (which in itself is painful), but the associated feather loss increases susceptibility to further injury, particularly if panic reactions lead to trampling and clawing. Finally, FP may lead to cannibalism - birds may be literally pecked to death if this catastrophic phenomenon develops. Remedial measures currently practised by the poultry industry have associated welfare problems. For example, beak trimming, which involves partial amputation of the beak, is a widely practised and effective control measure. However, it causes pain both during and after the operation. FP is also reduced by keeping birds under dim light but this practice impoverishes the visual environment and it can cause eye abnormalities, such as dimlight buphthalmos. There is strong pressure in the EU to ban battery cages and develop viable alternative housing systems. However, the increased risk of FP is a major obstacle to the widespread adoption of alternative housing, such as free range, aviaries, percheries, etc. It is therefore imperative that we improve our understanding of this behavioural problem thereby maximising our attempts to solve it.

The main objective of this project is to improve the welfare of laying hens by increasing our understanding of the internal (originating within the bird) and external (originating from its environment) variables underpinning the development and reduction of FP.

1. Investigation of individual characteristics associated with low and high feather pecking

    - The behavioural and physiological characteristics of low FP (LFP) and high FP (HFP) laying hens will be compared in order to investigate whether key characteristics can be found that predict the likelihood of FP development.
    - The relationships between behavioural and physiological characteristics and FP will be examined in a commercial strain. FP will be recorded in commercial flocks of adult laying hens and high and low FP chickens will be categorised. The physiological and behavioural characteristics will then be compared.
2. Evaluation of attributes of inanimate stimuli modulating pecking preferences
    - By studying the targeting of pecking (e.g. at the food, the general environment, or birds) in growing birds of the LFP and HFP lines, critical developmental stages at which these lines diverge in the expression of FP will be identified.
    - The attractiveness (peck-eliciting properties) of various inanimate stimuli (e.g. string, beads, plastic tubes) and of variations in their component features (e.g. colour, texture, complexity, location) will be compared in chicks and adult hens from a commercial line. The stability (over time) of observed pecking preferences will be established.
    - Based on these results, a putative attractive pecking device capable of sustaining the birds' interest will be developed.
    - The comparitive peck-eliciting properties of an animate stimulus, e.g. bird with disturbed feathers, and of the pecking device, will be assessed in commercial adult birds.
    - The efficacy of the pecking device, under experimental conditions calculated to induce aggression, in diverting pecking away from companions will be assessed in adult birds of a commercial line.
3. Determination of the attractive properties of pecked birds and social transmission of FP
    - The important physical attributes of animate (bird) stimuli that elicit pecking will be identified.
    - Combinations of LFP and HFP laying hens will be used to determine whether FP spreads within a group.
4. Evaluation of potential remedial measures and formulation of recommendations for their practical application
    - It will be evaluated whether birds with appropriate behavioural and physiological characteristics show reduced FP under commercial conditions.
    - Potential efficacy of strategies intended to divert pecking away from conspecifics under commercial conditions will be evaluated with birds that have not been beak trimmed.
    - The potential cost/benefit of manipulation of the social environment will be evaluated.
    - The results of subtasks will be combined to formulate recommendations for the poultry industry.

Current situation/results:
General experimental techniques and expertise were succesfully developed and implemented. Several concrete results have already been obtained at this stage of the project. It has been shown that total pecking behaviour and gentle feather pecking and aggressive pecking were already significantly elevated in the HFP birds at 14 days old and remained higher. Also, a relevant conclusion is that damage to feathers does elicit feather pecking, and that the most preferred area on which gentle feather pecking occurs is the rump (mostly when feathers were ruffled or removed). The areas that are most severely feather pecked are those where the tail feathers are cut very short, and where the rump feathers are ruffled or removed.
Clear results came from the systematic investigation of the peck-eliciting properties of a range of stimuli. It was shown, for instance, that string was more attractive than lengths of chain or beads; white or yellow string attracted much more interest than blue, red or green, and single-coloured devices were preferred to combinations of colours.

Institute for animal science and health (ID-Lelystad)
Edelhertweg 15
NL-8200 AB Lelystad
Tel.: +31 320 23 82 38
Fax: +31 320 23 82 08


  • Robert Bryan JONES
    Roslin Institute (Edinburgh)
    UK-EH25 9PS Roslin-Midlothian
    Tel.: +44 1315 27 44 66
    Fax: +44 1314 40 04 34

  • Linda KEELING
    Swedish University of Agricultural Sciences
    PO Box 234
    S-53223 Skara
    Tel.: +46 51 16 72 20
    Fax: +46 51 16 72 04


  • Gerard ALBERS
    Veerstraat 38
    NL-5831 JN Boxmeer
    Tel.: +31 485 58 99 22
    Fax: +31 485 57 52 05

    Lohmann Tierzucht GmbH
    Am Seedeich 9
    D-27454 Cuxhaven
    Tel.:+49 472 150 50
    Fax: +49 472 13 88 52
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