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.
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.
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.
Evaluation of attributes of inanimate stimuli modulating pecking
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.
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.
Determination of the attractive properties of pecked birds and
social transmission of FP
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.
The important physical attributes of animate (bird) stimuli that
elicit pecking will be identified.
Evaluation of potential remedial measures and formulation of
recommendations for their practical application
Combinations of LFP and HFP laying hens will be used to determine
whether FP spreads within a group.
It will be evaluated whether birds with appropriate behavioural
and physiological characteristics show reduced FP under commercial
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.
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.
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
for animal science and health (ID-Lelystad)
+31 320 23 82 38
+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
Tel.: +46 51 16 72 20
Fax: +46 51 16 72 04
- Gerard ALBERS
NL-5831 JN Boxmeer
Tel.: +31 485 58 99 22
Fax: +31 485 57 52 05
- Rudolf PREISINGER
Lohmann Tierzucht GmbH
Am Seedeich 9
Tel.:+49 472 150 50
Fax: +49 472 13 88 52