back to the Council of Europe internet portal
Legal affairs
Legal co-operation
Biological safety and use of animals
Laboratory animals


Resolution on the accommodation
and care of laboratory animals

adopted by the Multilateral Consultation on 30 May 1997

The Parties to the European Convention for the protection of vertebrate animals used for experimental or other scientific purposes, by virtue of its Article 30;

Recognising that the provisions of this Article imply the monitoring of the implementation of the provisions, the adaptation of the Convention to changing circumstances and new scientific evidence and the development of common and coordinated programmes in the field covered by the Convention;

Considering that the "Guidelines for accommodation and care of animals" presented in Appendix A of the Convention has proved to be very useful and widely applied;

Aware however that scientific knowledge and experience have moved since 1986 and the entry into force of the Convention;

Anxious to improve the implementation of the Convention taking into account developments in knowledge concerning biological needs of the animals including ethological needs;

Recalling that Article 5 of the Convention requires that animals be provided with accommodation and care appropriate to their health and welfare;

Recalling that the provisions in Article 5 paragraph 1 of the Convention requires that "any restriction on the extent to which an animal can satisfy its physiological an ethological needs shall be limited as far as practicable";

Taking note of the report of the International Workshop on laboratory animal welfare held in Berlin in May 1993 (Berlin report) and of the recommendations presented in its conclusions;

Recognising that recommendations of that report will improve laboratory animals welfare;

Considering that an agreement on common principles based on these recommendations and complementing the guidelines for accommodation and care for animals presented in Appendix A to the Convention will facilitate and harmonise the implementation of Article 5 of the Convention;

Anxious however to encourage further research in those issues raised in the Berlin report where scientific evidence is lacking;

Resolve as follows:

The responsibility of the establishment and persons carrying out scientific procedures on animals is to maximise the overall benefit for "animals" as "individuals" and as a "group", with the 3R principle as a permanent concern and considering that the relevance and high quality of scientific results will facilitate the achievement of this rule.

Enrichment of the environment:

Special relevance should be given to the enrichment of the environment of the respective species according to their needs:

- social interaction
- activity-related use of the space
- appropriate stimuli and materials.

Therefore group-housing, even pair-housing, is preferable to individual housing for all gregarious species normally manifesting social behaviour, as long as the groups are stable and harmonious. Where for behavioural or inescapable requirements of a scientific protocol group-housing is not possible, consideration should be given to accommodating conspecifics within sight, sound or smell of one another.

Structuring of the cage space to allow its activity - related use as well as introducing appropriate stimuli and materials should be encouraged, but with care taken to confirm that these initiatives don't have deleterious effects on welfare. As the particular needs of given species and strains have to be considered, guidelines should never replace close observation of the particular animals involved, continued throughout their lives.

Exhaustive research on all species and strains is difficult to achieve, but this should not inhibit or prevent local initiatives for improving housing conditions.

General recommendations and comments


- ventilation rate in the animal room should be appropriate to stocking density in accordance with the total caloric output of the animals. Additional attention should be paid to the ventilation within the cage with respect to different caging systems.


- Animals should be handled or be in social contact with humans on a regular basis, with particular attention to the socialization period in species such as cats and dogs.

Recommendations and comments on different groups of species:

With respect to individual species - the following recommendations and comments should be taken into consideration:


- Rodents should be kept in cages rather than pens, guinea-pigs excepted. The cages should be made of easy to clean material and their design should allow proper inspection of the animals without unnecessarily disturbing them.

- They should be provided with solid floors with bedding instead of grid floors, special circumstances excepted.

- Gregarious species should be group-housed, as long as the group are stable and harmonious, which can be achieved with difficulty in male rats and mice, and female hamsters. Where the experimental procedures or welfare requirements make it impossible, consideration should be given to accommodating conspecifics within sight, sound or smell of one another.

- Encouragement should be given to break up the interior space of a cage by introducing objects such as platforms, tubes, boxes, etc. and attempts should be made to provide environmental enrichment with objects to explore, carry or transform, unless negative effects are observed on welfare or on the intended scientific use.

- High hygiene standards should be maintained. However, it may be advisable to maintain odour patterns left by the animals.

- Special attention should be paid to ensuring that the lighting intensity particularly on the top row of cages is not too high. Maximum light intensity should not exceed 350 Lux measured 1 metre from the floor. Provision should be made for shaded areas within the cage to allow the animals to withdraw.


- Young and female rabbits should be housed in socially harmonious groups, unless the experimental procedure or welfare requirements make this impossible.

- Wire floors without the provision of a solid resting area should not be used for rabbits. The materials, design and construction of slatted or perforated floors should provide surfaces which do not produce welfare problems.

- Pens as well as cages should include environmental enrichment material e.g. roughage, sticks, an area for withdrawal and nesting material.


- Cats should be housed in pens in socially harmonious groups unless the experimental procedures or welfare requirements make this impossible.
There should be 0.8 sq. m. floor area per weaned cat for group-housed animals. The minimum height should be 1.5 m. and pens should be so equipped that the three dimensions can be used.

- Pens should provide semi-closed structures for privacy, clawing substrate, objects to play with and enough places for feeding, drinking, urination, defecation and lying down to avoid competition.

- If cages have to be used and exercise is not possible for experimental reasons, cage heights should allow the animal to stand up at full stretch.


- Dogs should be housed in socially harmonious groups, unless the experimental procedures or welfare requirements make this impossible.

- Dogs should be exercised at least daily. Under no circumstances should dogs be caged without exercise for more than 14 days. Preferably, dogs should be exercised with other dogs.

- Dog pens should allow some privacy for the animals. They should include playthings and structures, including elevated platforms.

- Solid floors should be used for dogs. The materials, design and construction of slatted or perforated floors should provide surfaces which do not produce welfare problems, and should supply a solid resting area.

Pigs (including minipigs)

- Pigs should be housed in stable, socially harmonious groups, adult boars excepted.

- Preferably they should be housed in pens, unless experimental procedures or welfare requirements make it impossible.

- They should be provided with enrichment such as straw, chains, balls, etc.


- Various structural elements such as perches and nesting sites, and the possibility of dustbathing, should be provided in the cages or pens whenever possible and appropriate.

Non-human primates

- The volume of cages (floor area, height) should take into account the specific needs of the different species, the social composition of the group, the age of the individuals, the use of animals (breeding, stock, research and the nature and duration of the scientific procedure), and the need for enrichment.

- Primate cages should have environmental enrichment.

- Primates should be kept in stable social groups of compatible animals while taking into account the diversity of social structure between species. Single caging should be avoided unless a specific scientific justification is provided.


Research shall be encouraged in the areas where scientific evidence is lacking on the biological requirements
of the animals, considering also the changes in the use of animals for scientific purpose. To make the best use of available resources to determine the optimum housing conditions for laboratory animals, taking into account species, strains, current and future research needs, priority shall be given to the following areas:

- scientific validation of minimum cage sizes for rodents, as well as of minimal space per individual animal, taking into account social structure and role (sex, age, hierarchy...), cage structure etc;

- scientific validation of floor areas and cage heights for non-human primates, taking especially into account the biological and social differences between species and the purpose of housing (stock, breeding, use in procedures);

- the welfare impact of group housing compared to individual housing and the impact on the group of removing individuals or splitting up the group of animals after a period of time for experimental purposes;

- the impact of different cage structures on the welfare of rodents and non-human primates;

- the effect of introducing objects and structural elements into cages as environmental enrichment;

- the space requirements and environmental enrichment needs of dogs.