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Office of Animal Welfare

Environmental Enrichment for Sheep

I. Introduction/Purpose

The goal of environment enrichment for sheep is to maximize activity while increasing species-specific positive behavior and enhancing the animals’ well-being. The components of environmental enrichment for sheep include social housing, toys and food treats.

II. Procedures

A. All sheep will be provided with environmental enrichment unless:

  1. The investigator provides scientific justification to the IACUC as to why enrichment is not compatible with the goals of the study and the IACUC approves the variance.
    OR
  2. If in the opinion of the Attending Veterinarian, or designee, environmental enrichment will adversely affect the health or well-being of the animals. All such cases will be reviewed at least monthly by the veterinary staff.

B. Social Housing

  1. The dominant social characteristic of sheep is their flocking behavior. Sheep should not be housed in isolation unless justified and approved (see section A above). If an animal must be singly housed, sheep should be able to be in visual and auditory contact with other sheep.
  2. Females that arrive together are to be housed together.
  3. Immature males or castrated males that arrive together are to be housed together.
  4. Females or immature/castrated males that arrive separately are to be introduced to social housing after a 24hr rest period. Social introduction will be done in collaboration with veterinary services.
  5. Mature rams are to be housed singly.
  6. Singly housed animals will be provided extra enrichment in the form of a food puzzle a minimum of once a week.

C. Toys

  1. All sheep are to be provided with an assortment of approved toys such as Jolly Balls, Likit or sections of hanging fire hose, or equivalent toys.
  2. Toys are to be checked daily for fecal contamination and removed if contaminated.
  3. Toys must be rotated weekly for sanitizing and to prevent boredom.
  4. Some animals may react aversively to certain toys. Husbandry and/or Veterinary Services will evaluate individual animals’ responses to enrichment items, and remove items that animals are reacting negatively towards. These animals will be provided with alternative toys, or alternative forms of enrichment.

D. Food treats

  1. Food treats are to be provided at least 2 times weekly.
  2. Food treats will consist of the following:

​​a. Fruits

(1) Fruit should be provided only in small quantities and not daily, to prevent excess intake of simple carbohydrates which can lead to rumen acidosis.
(2) Remove seeds, pits, and cores from applicable fruits (apples, pears, peaches).
(3) Larger round fruits must be cut into smaller pieces to avoid esophageal obstructions (choke).

b. Vegetables –can include celery, spinach, pumpkins, squash, and cucumbers

(1) The following vegetables should be avoided: beets, sugar beets, lettuce, cabbage, potatoes, carrots, rape, turnips, broccoli, kale, garlic, and onion; small, vegetables which could potentially cause an esophageal obstruction (choke)

E. ​​​Music

  1. Music is provided to reduce the stress response the animals may exhibit to activity in the room or to hallway noises.
  2. Music is to be provided for 4-6 hours daily.
  3. Music provided is to be instrumental compositions (e.g. Mozart, Bach, etc) or nature sounds (nature sounds cannot include predator sounds from animals such as dogs, coyotes, wolves, etc.), or compilations from the Approved Environmental Enrichment Music by Species document, approved by the Attending Veterinarian.
  4. Music must always be played at a level below 80 decibels.

​​F. Foraging

  1. Sheep will have ad libidum access to roughage (hay, alfalfa)

a. A sheep’s natural diet is predominately roughage, and they spend the majority of their time grazing or ruminating.

2. Foraging options include:

a. Roughage on bottom of enclosure mixed with straw or the bedding.
b. A foraging/feeder bin the sheep can pull roughage through
c. Providing grain/concentrate feed in a pale with forage covering it, to allow the sheep to browse through the forage for the feed.
d. One of these options will be available daily.

G. Implementation of enrichment must be recorded on the daily room log and the environmental enrichment log in the animal housing room.

H. New environmental enrichment items can be added with the approval of the Chair of the Environmental Enrichment Committee and the Attending Veterinarian.

III. References

  1. “The Effects of Music on Cognitive Performance: Insight from Neurobiological and Animal Studies”, Nikki S. Rickard, Samia R. Toukhasti and Simone E. Field, Behavioral and Cognitive Neuroscience Reviews Volume 4 Number 4, December 2005 235-261
  2. “Storey’s Guide to Raising Sheep”, Paula Simmons and Carol Ekarius, ©2009, 2001
  3. “Compassion Makes a Difference”: Discussions by the Laboratory Animal Refinement and Enrichment Forum Volume III, ©2013

II. Approval/Review Dates

SOP Created: 02/10/2017
Last Reviewed/Revised by the IACUC: 02/16/2023

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