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I. Purpose

This document provides guidance for the appropriate housing density for cages used to accommodate rodents.

II. Scope

This guidance applies to all rodent species listed.

III. Guidance

The Guide  defines the recommended minimum space for commonly used laboratory rodents housed in groups. If they are housed singly or in small groups or exceed the weights in the table, more space per animal may be required, while larger groups may be housed at slightly higher densities.

IV. Species

A. Mice

 

          Weight           

(g)

           Max # mice              

(81 in2)
Mice in Groups

<10

 12
  Up to 15 10
  Up to 25 5
  >25 5
Female + litter Or Breeding Group - (harem or trio)   1

Breeding Schemes and Management: See Mouse Breeding Guideline

 

B. Rats    

 

                 Weight           

(g)

             Max # rats            

(286 in2)
Rats in groups           <100 16
  Up to 200 12
 

Up to 300

 9
  Up to 400 7
  Up to 500 4
  >500 3

 

C. Guinea Pigs

 

            Weight           

(g)

            Max # guinea pigs           

(286 in2)
Guinea pigs        Up to 350 4
  >350 2

 

V. References

Guide for the Care and Use of Laboratory Animals, National Academy of Sciences, 2011

Animal Welfare Act and Animal Welfare Regulations, March 15, 2022

 

IACUC Approval Date:  03/17/2021

Review Date:  03/21/2024

Issue Date:  03/22/2024