Table 1. Density and floor space according to cage type^a.

	Duplex cage			Shoebox cage
Density group	Floor space per mouse		Mice per cage	Floor space per mouse		Mice per cage
	cm2	in2		cm2	in2
1	83.2	12.9	4	83.9	13.0	6
2	47.7	7.4	7	50.3	7.8	10
3	36.8	5.7	9	36.1	5.6	14
4	30.3	4.7	11	31.6	4.9	16
Total mice per cage type			3,720			5,520
Total number of cages			480			480

^aThe duplex cage consists of two separate cages; each has a floor area of 333.6 cm² (51.6 in²). The shoebox cage has a floor area of 503.7 cm² (78.1 in²).

The housing density of Density group 1 is almost equal to that recommended by the Guide, which is 77.4 cm² for mice between 15 and 25 g. Housing densities of groups 2, 3, and 4 are approximately 2.0-, 2.6-, and 3-fold greater. Numbers of mice were chosen to produce nearly equivalent densities between the two cage types. To complete replicate sets of cage densities, mice were obtained in groups of 31 for duplex cages and in groups of 46 for shoebox cages.