07_Welfare of laying hens is improved by a ban on battery cages.
Submitting InstitutionUniversity of Edinburgh
Unit of AssessmentBiological Sciences
Summary Impact TypeEnvironmental
Research Subject Area(s)
Chemical Sciences: Inorganic Chemistry
Summary of the impact
Impact on health and welfare: The health and welfare of laying
hens has been improved by the EU-wide ban on the use of small, barren
battery cages, enabled by UoE research on the relationship between cage
design and welfare.
Impact on public policy and services: The EU banned conventional
battery cages for laying hens through a directive that came into effect on
1st January 2012. New Zealand followed with its own ban in
Impact on production: Farmers have changed from housing laying
hens in battery cages to using more welfare-friendly furnished cages or
Impact on commerce: In the UK, over £400M has been spent to meet
the standards laid down by the EU directive.
Beneficiaries: Laying hens in Europe and New Zealand; farmers who
use furnished cages as an economically efficient alternative to
Significance and Reach: The improved welfare of over 1.3 billion
laying hens in Europe and New Zealand.
Attribution: All research was led by Dr Michael Appleby,
University of Edinburgh (1984-2001), with collaborators at the Roslin
Institute (now UoE), Uppsala and Bristol.
UoE research led by Dr Mike Appleby investigated the welfare of laying
hens in commercial egg farming, comparing different types of cages,
free-range and deep litter systems. His work with Hughes and Smith of the
Roslin Institute (now also UoE), published in 1993 , focused on the
effect of modified cages holding small groups of hens on hen behaviour and
welfare. This research adopted a stage-by-stage, systematic approach to
the design of modified cages. Recommendations for cages delivering
improved welfare arising from this research included increased area and
height compared to conventional cages, and inclusion of a perch, a nest
box and a dust bath.
In a 1993 review paper (Animal Welfare, 1993, 2; 67-80), Appleby argued
that in the current state of development of alternative systems, modifying
cages for laying hens could on balance be more beneficial to the welfare
of hens than banning cages completely. Legislation to specify the
facilities which should be provided for laying hens would address the main
welfare issues, thereby banning battery cages but not furnished cages.
Subsequent work  described further behavioural, welfare and production
studies which trialled the Edinburgh Modified Cage (EMC), a novel
`enriched' cage design housing a perch, nest box and dustbath, with the
latter two being controlled automatically. EMC was 600 mm wide, 450 mm
deep and 450 mm high at the rear; it had a softwood perch and at one side
a 250 mm wide nest box (containing litter or artificial turf) with a dust
bath directly above. It housed 4 birds and provided 675 cm2/bird
in the main cage with an additional 281 cm2 /bird in the nest
box. The UoE researchers showed that hens performed natural pre-laying
behaviour in the cages with nest boxes, preferentially laid within the
next box (96% of layings), and that the dust baths were used well, with
three times as many hens performing bathing behaviours compared to the
control group. 98% of hens roosted on the perch overnight.
Paper  in collaboration with Tauson (Swedish University of
Agricultural Sciences) showed that modified enriched cages were
commercially viable. In 1996 , UoE research showed through trials of
more than 3500 hens that the behaviour and health of hens were improved in
the modified cages compared either to conventional battery cages or to
large `get away' cages housing 16-20 hens which were then perceived to
offer a more `natural' environment.
Appleby published further work on the Edinburgh Modified Cage regarding
group size and space allowance in 1998 . It showed that the hens used
the facilities well, they had settled nesting behaviour that is a good
welfare sign, and their condition was improved compared to those hens in
conventional cages. Egg production was above breeders' standards and
although egg production would cost more than in conventional battery
cages, it was less than the cost of free range.
In 2002 the results of a 3-year trial of furnished cages for laying hens
funded by the UK Ministry of Agriculture, Fisheries and Food were
published . This study, which was led by Appleby whilst at UoE, took
place at the Poultry Research Centre at ADAS Gleadthorpe in collaboration
with Hughes and with Nicol (Bristol Veterinary School). The study
concluded that behaviour was more unrestricted and varied, and physical
condition was better, in furnished than in conventional cages and that
furnished cages protected the welfare of laying hens.
People: Dr Michael Appleby (lecturer, UoE) 1984-2001, led all of the
research. He is now Chief Scientific Adviser at the World Society for the
Protection of Animals (WSPA), London and an honorary fellow at the
University of Edinburgh. Key collaborators: Barry Hughes and S Smith,
Roslin Institute (UoE); Ragnar Tauson, Uppsala; Christine Nicol,
University of Bristol Veterinary School.
References to the research
2. Appleby, M.C. & Hughes, B.O. (1995). The Edinburgh Modified Cage
for laying hens. British Poultry Science 36, 707-718. doi:
43 Scopus citations on 19/09/2013.
3. Abrahamsson, P., Tauson, R. & Appleby, M.C. (1995). Performance of
four hybrids of laying hens in modified and conventional cages. Acta
Agriculturae Scandinavica Section A — Animal Science 45 (4) 286-296.
34 Web of Science citations on 01/10/2013
4. Abrahamsson, P., Tauson, R. & Appleby, M.C. (1996). Behaviour,
health and integument of four hybrids of laying hens in modified and
conventional cages. British Poultry Science 37, 521-540.
72 Scopus citations on 19/09/2013.
5. Appleby, M.C. (1998). The Edinburgh Modified Cage: effects of
group size and space allowance on brown laying hens. Journal of Applied
Poultry Research 7, 152-161.
or available on request
18 Scopus citations on 19/09/2013.
6. Appleby, M.C., Walker, A.W., Nicol, C.J., Lindberg, A.C., Freire, R.,
Hughes, B.O. & Elson, H.A. (2002). Development of furnished cages for
laying hens. British Poultry Science 43, 489-500. DOI:
74 Scopus citations on 19/09/2013.
Details of the impact
By showing that it is possible to minimise the main disadvantages of
cages whilst keeping the advantages, UoE-led research into the design and
development of furnished cages has led to an improvement in the welfare of
all commercial laying hens in Europe [a,b]. The policy impact of this work
started to take effect in 1996 but the main animal welfare (and
commercial) impact has been in the period 2008-13, arising from EU
legislation banning battery cages which came into effect in 2012.
It is widely accepted that conventional battery cages for housing laying
hens cause many welfare problems and they can compromise many or all of
the Farm Animal Welfare Council (FAWC 1997) "Five Freedoms": that farm
animals should have freedom from hunger and thirst, from discomfort, from
pain, injury or disease and from fear and distress, and freedom to express
normal behaviour. Battery cages do not even meet the earlier
recommendation of the Brambell Report (HMSO, 1965), that an animal should
be able without difficulty to stand up, lie down, turn around, groom and
stretch their limbs. However, non-cage systems also have welfare issues.
UoE research, along with other groups, showed prior to 1993 that
free-range and deep litter systems carry with them welfare problems such
as cannibalism. To minimise the risk of cannibalism, beak trimming is
performed. This is itself a welfare issue.
In 1996, the EU's Scientific Veterinary Committee (Animal Welfare
Section) reviewed the welfare of laying hens in cages and reported that
"because of its small size and its barrenness, the battery cage as used at
present has inherent severe disadvantages for the welfare of hens. To
retain the advantages of cages and overcome most of the behavioural
deficiencies, modified enriched cages [our italics] are showing
good potential in relation to both welfare and production" [c]. They also
reported on other housing systems "aviaries, percheries, deep litter or
free range systems provide... improved possibility for the birds to
express a wider range of behaviour patterns ... [However] mainly because
of the risk of feather pecking and cannibalism, these systems have severe
disadvantages for the welfare of laying hens." This 1996 report directly
references the UoE research published since 1993   .
Sweden was the first country to introduce furnished cages on a large,
commercial scale from 1998; the UoE work was influential in the design of
these furnished cages [b]. In late 1998 a number of representatives of the
Council of Ministers and the Commission's Directorate-General for
Agriculture visited Sweden to see the advantages and disadvantages of
furnished cages for themselves. This led to a 1999 directive by the EU,
which was strongly based on advice from this Scientific Veterinary
Committee [a,b]. In 1999, the EU passed a directive (1999/74/EC) leading
to the banning of conventional battery cages because of the welfare issues
associated with them and specifying the minimum requirements required for
furnished cages. This directive banned conventional battery cages in the
EU with effect from January 1st 2012 after a 13-year phase-out
period. As an alternative to battery cages, the directive allowed either
non-cage systems or furnished
cages. Under the directive, furnished cages must provide at least
750 cm2 per hen, of which 600 cm2 is 45 cm high, a
nest, a littered area for scratching and pecking, 15 cm of perch and 12 cm
of food trough per hen and a claw shortening device [d]. This is a close
match to the original Edinburgh Modified Cage design [2, 5]. The Guardian
newspaper has described this as "one of the most significant pieces of
animal welfare legislation ever passed"
The EU directive was passed despite opposition from the egg industry of
Europe and worldwide, mainly due to the increased cost of using systems
other than battery cages. A contemporary BBC news article reports that
"The European Commission had called for an increase in the size of battery
hen cages ... But MEPs went a step further and agreed by a two-thirds
majority to ban such cages altogether". The availability of the
economically-viable furnished cage design derived from UoE research [4,
6], with its proven welfare benefits, enabled the full battery cage ban by
providing an economically-viable but high-welfare standard cage,
mitigating the economic impact that a ban on any caged system would have
had, and making it possible to implement the battery ban without having
such an adverse cost impact that it would have become more difficult for
the EU to protect its egg industry against competition from the rest of
the world. Without the option of the furnished cage, it is probable the
battery cage ban would not have been passed into law.
EU-wide there were 240 million laying hens housed in battery cages in
2006, representing 80% of the EU flock [Farm Animal Welfare Council (FAWC)
figures]. The number of hens housed in furnished systems has risen during
the REF period as a result of the phasing out of battery cages prior to
the 2012 implementation date of the ban: from 0% in 2006 to 14.3% (72.8
million) in 2010 and 42.3% (210 million) in 2012 [e]. The number in
battery cages has decreased throughout the period: 32.4% (165 million) in
2010; 11.3% (46.5 million) in 2011; 0% in 2012. Other hens are now in
barns, free-range or other approved systems. In the UK alone, over £400M
has been spent to meet the standards laid down for the 2012 EU ban. DEFRA
figures for 2012 indicate that 48.5% of UK eggs laid come from furnished
cages; this compares with 9% in 2009 [FAWC].
New Zealand has also acted to ban battery cages in favour of free range,
barn, or enriched-cage systems. The New Zealand government ruled that from
7th December 2012, no new battery cages could be installed in
In 2012 there were approximately 500 million laying hens in the EU,
including 34.8 million in the UK [f]. The UoE research has led to the
increased welfare of some 1.3 billion laying hens to date throughout
Europe in the period January 2008 to July 2013.
Sources to corroborate the impact
The Tiny URLs provide a link to archived web content, which should be
accessed if the original web content is no longer available.
a) Contact to confirm that UoE research influenced the design and
implementation of the EU-wide use of furnished cages: Director, Animal
Welfare Unit, European Commission DG Sanco.
b) Contact to confirm that UoE research influenced the design and
implementation of the EU-wide use of furnished cages: Inst för HUV,
c) The report of the European Commission, Scientific Veterinary Committee
Animal Welfare Section. Report on the welfare of laying hens (1996).
Directorate-general for Agriculture VI/BII.2. can be found at: http://tinyurl.com/og77dxy
[copy of pdf also available on request]
d) EU 1999/74/EC directive for "Laying down minimum standards for laying
[copy of pdf also available on request]
e) EU figures for laying hens: http://www.eepa.info/Statistics.aspx
(Miscellaneous section/Laying hens by way of keeping) or http://tinyurl.com/qztwe49
f) UK figures for laying hens: https://www.gov.uk/government/publications/egg-statistics