Figure 3.

Measurement of intracage parameters. (A) Rubber tubing connected to the Drager X-am 5000 ammonia reader; the pump is fed through the water grommet in the back of the cage. Readings with the tip of the rubber hose are performed over the nest and latrine areas (or the area opposite the nest if an obvious latrine could not be identified) immediately after removal from the rack (within ∼30 s). (B) Colorimetric ammonia measurement from the center of the cage. The colorimetric card changes color with rising ammonia levels; that is, yellow, 0 to 1 ppm; light green, 1 to 25 ppm; dark green, 25 to 50 ppm; and blue, >50 ppm. (C) CO₂ sensor measurement from the center of the cage.