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Social Housing Standard


Provide clarification on the requirement to social house animals.


The Guide for the Care and Use of Laboratory Animals (NRC, 2011) states that, “Appropriate social interactions among members of the same species (conspecifics) are essential to normal development and well-being (Bayne et al. 1995; Hall 1998; Novak et al. 2006). When selecting a suitable social environment, attention should be given to whether the animals are naturally territorial or communal and whether they should be housed singly, in pairs, or in groups. An understanding of species-typical natural social behavior (e.g., natural social composition, population density, ability to disperse, familiarity, and social ranking) is key to successful social housing.”


For the purpose of this policy, social species include the following: dogs, cats , pigs (excluding boars), sheep, goats, cattle, (excluding dairy calves), horses (excluding stallions), alpacas, llamas, rabbits (excluding bucks and excluding does kept for less than 6 months), ferrets, rodents (excluding male mice used for breeding and female hamsters), marsupials (excluding monodelphis), chickens (excluding roosters), psittacines, quail, ducks, turkeys, fish, and songbirds. Social housing refers to housing animals in same sex (excluding sterilized individuals), compatible pairs or groups in the animals’ primary enclosure and allowing direct contact and interaction.

Social housing is the default method of housing, however, exceptions exist and are based on criteria such as social incompatibility, veterinary concerns regarding animal well-being, or scientific necessity as approved by the IACUC. 

If singly housing animals is deemed necessary, it should be limited to the minimum period necessary to achieve the objective and animals should be rehoused with appropriate cage/pen mates as soon as possible. During single housing, every effort should be made to maintain the following with animals of the same species:

  • visual contact 
  • auditory contact 
  • olfactory contact 
  • protected tactile contact

In the absence of other animals, additional enrichment should be offered to a single housed animal. Examples of such enrichment may include additional positive interaction with humans, periodic release into larger enclosures, or supplemental enrichment items. 

All singly housed animals must have documentation to indicate the reason for non-social housing. This could include:

  • “Single housing” card on their primary enclosure/with their cage card
  • Listed on the room door sign to indicate the reason for non-social housing. 

For animals without a permanent record, the “Single Housing” card serves as a social housing record history for the life of the animal. If the animal has a permanent record, the reason for single housing must also be written in each animal’s permanent record. The cards and/or the records must be readily available for review by the IACUC, UAV, and outside regulators upon request.

Exceptions to Social Housing

The IACUC approves single housing of social animals for standard agricultural husbandry practices or situations where attempts to socially house the animals could jeopardize animal welfare. When animals are single housed for such reasons, a specific justification in the animal use protocol and case by case approval by the IACUC are not required. Examples of such situations include, but are not limited to: 

  • separation of aggressive or incompatible animals
  • quarantine prior to entering or reentering a facility or herd
  • pregnant females separated to prevent overcrowding following birth of offspring or for the safety of offspring
  • individual housing in preparation for parturition
  • separation of littermates at weaning when the number of offspring does not allow for all animals in a litter to be placed with a compatible cage mate (single male weanlings
  • animals housed singly for short term recovery post-operatively; single housing must be for the minimum amount of time necessary for recovery and/or healing as determined by the PI in consultation with the Attending Veterinarian
  • When animals are left singly housed due to attrition of cage mates on study, or uneven experimental group sizes, consideration should be given to re-housing with other conspecifics when possible, depending upon the expected duration of the study. When re-pairing is not possible without disrupting the study, singly housing is acceptable for the remainder of the study.
  • individual housing for clinical reasons at the discretion of the Attending Veterinarian, or designated clinical veterinarian,based on medical concerns

Experimental Requirements: When single housing of social species (other than short term recovery from experimental manipulation) is necessary for experimental reasons, a scientific justification must be described in the animal use protocol, submitted for review and approval by the IACUC, and the single housing cannot begin until approval is granted by the IACUC for that protocol. 

References and Resources

DiVincenti L Jr, Rehrig A. Social Behavior of Adult Male New Zealand White Rabbits Housed in Groups or Pairs in the Laboratory. J Appl Anim Welf Sci. 2017 Jan-Mar;20(1):86-94. doi: 10.1080/10888705.2016.1247352. Epub 2016 Nov 9. PMID: 27827538.

Kappel S, Hawkins P, Mendl MT. To Group or Not to Group? Good Practice for Housing Male Laboratory Mice. Animals (Basel). 2017 Nov 24;7(12):88. 

DOI: 10.3390/ani7120088