14.161—Primary enclosures.

(a) Except as provided in § 14.106(j), ventilation openings must be located on at least two walls of a primary enclosure. When the required ventilation openings are located on two opposite walls of the primary enclosure, these ventilation openings shall comprise at least 16 percent of the total surface area of each ventilated wall. When openings are located on all four walls of the enclosure, the openings shall comprise at least 8 percent of the total surface area of each wall. At least one-third of the minimum area required for ventilation shall be located on the lower one-half of the enclosure, and at least one-third of the total minimum area required for ventilation shall be located on the upper one-half of the enclosure.
Density Guidelines for Rodents
Max. No. Space/Animal Ht. of Box
cm /2/ in /2/ cm in
wt. in grams of rodent:
220 or less 20 194 30 15 6
220-450 12 388 60 20 8
450-1000 6 770 120 25 10
1,000-5,000 2 2,310 360 30 12