Identifying Single Housed Animals SOP

Unit for Laboratory Animal Medicine
Apr 23, 2021 12:00 am

To describe the procedures for classifying animals that are single housed and labeling cages appropriately. All single housed animals on campus must be identified with the reason they are housed singly.

  • Responsibility

    1. Husbandry Personnel
    2. Veterinary Personnel
    3. Investigative Personnel
  • Glossary Definitions


    A colored, plastic card placed over animal cage cards that aid in communication between husbandry, ULAM veterinary, and Investigative personnel. Acetate colors correspond to a specific animal care procedure and could be red, green, clear, yellow or blue. In certain settings, such as aquatic or outdoor housing areas, acetates may not be easily utilized. In those cases, animal identification procedures should be agreed upon by veterinary and investigative personnel as needed and communications will be documented in relevant medical records.

  • Procedures

    If there is not a laboratory managed procedure for identifying singly housed animals, follow the steps below.

    1. Classifying Single Housed Animals

    1. Identify single housed animals using one of the following exemption codes:
      1. A = Attrition: Animal is now single housed due to lack of suitable littermate, death, weaning, separation, or new arrivals shipped separately.
        1. Personnel may contact veterinary personnel if pairing or group housing animals is desired following attrition.
      2. F = Fighting: Includes males and females that have been separated due to aggression or demonstrated and documented social incompatibility.
      3. P = Protocol Specific Reasons: Animals must be individually housed due to approved scientific and/or protocol specific reasons.
      4. V = Veterinary Treatment: Animals must be individually housed due to ongoing veterinary treatments.
      5. B = Breeding: Animal must be individually housed either because it is a stud male that will fight with other males and is not currently being bred to a female or because it is a pregnant female removed from its home cages to prevent overcrowding resulting from multiple litters in a cage.

    2. Labeling Cage Cards Containing Single Housed Animals

    1. Any personnel creating a single housed animal:
      1. Affix a blue plastic Post-It® Filing Tab denoting the date and appropriate exemption code letter to top of cage card.
      2. Affix a blue plastic Post-It® Filing Tab denoting the date and appropriate exemption code letter to a yellow acetate and place on the back of the animal room door for groups of animals that are single housed with the same exemption code.
        1. Ensure acetate contains clarifying information of what cages the exemption code and date pertain to (e.g., all male rats for PI ‘X’ or all cages on rack ‘X’).
    2. Husbandry personnel upon finding a single housed animal with no accompanying exemption code:
      1. Place a blue acetate vertically behind the cage card denoting the date.
      2. Affix a blank blue plastic Post-It® Filing Tab to the top of the cage card.
    3. Investigative personnel record the date and correct exemption code on the blank blue plastic Post-It® Filing Tab that was placed by the husbandry personnel.
      1. Husbandry personnel notify the husbandry supervisors via the building husbandry supervisor email address if investigative personnel have not labeled cages appropriately within 7 days, include the following information in the email:
        1. Principal Investigator (PI)
        2. Room location
        3. Laboratory contact
      2. Husbandry supervisors contact and inform investigative personnel of the missing exemption code.
        1. Husbandry personnel record the date the investigative personnel was contacted on the vertical blue acetate.
      3. Husbandry personnel re-report the cage to the husbandry supervisors if not appropriately labeled after an additional 7 days from the date laboratory was first contacted.
      4. Husbandry supervisor reports the laboratory to the facility faculty veterinarian for follow-up.
        1. The facility faculty veterinarian determines if the concern is reported to the IACUC,
    4. Remove the vertical blue acetate when the blue plastic Post-It® Filing Tab has the appropriate documentation.
    5. Remove the blue plastic Post-It® Filing Tab if the animal is no longer single housed.

    3. Enrichment

    1. Provide single housed mammals with at least two enrichment items.
      1. Place the additional enrichment item(s) at the next cage change from when the mammal was noted to be single housed and the
      2. Recode the additional enrichment item(s) on the Animal Room Log sheet.
      3. See Environmental Enrichment for Animals SOP for details.
  • Appendix A: Additional Enrichment Signage

Topic: Husbandry

If you have questions or comments about this document, contact ULAM Veterinary Staff (email