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Background:
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.
Objectives:
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.
Description:
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.
Coordinator
Harry BLOKHUIS
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
E-mail: h.j.blokhuis@id.wag-ur.nl
Partners
-
Robert Bryan JONES
Roslin Institute (Edinburgh)
UK-EH25
9PS Roslin-Midlothian
Tel.: +44 1315 27 44 66
Fax: +44 1314
40 04 34
E-mail: bryan.jones@bbsrc.ac.uk
-
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
E-mail: linda.keeling@hmh.slu.se
Subcontractors
-
Gerard ALBERS
EURIBRID B.V.
Veerstraat 38
NL-5831 JN
Boxmeer
Tel.: +31 485 58 99 22
Fax: +31 485 57 52
05
E-mail: gerard.albers@nutreco.nl
- Rudolf PREISINGER
Lohmann Tierzucht GmbH
Am Seedeich
9
D-27454 Cuxhaven
Tel.:+49 472 150 50
Fax: +49 472 13 88
52
E-mail: preisinger@ltz.de
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