EFFECTS OF CAGE STOCKING DENSITY ON FEEDING BEHAVIORS OF GROUP-HOUSED LAYING HENS

Quantitative measurement of animal welfare continues to be a challenging task for both the animal agricultureindustry and the scientific community. Characterization of animal feeding behavior provides a comparative elucidation ofthe animals behavioral deviation from its norms and thus carries implications for its welfare. This study examines the effectsof cage stocking density (348, 387, 426, and 465 cm2; or 54, 60, 66, and 72 in.2 cage floor space per hen) on feeding behaviorof W-36 White Leghorn laying hens kept in groups of six hens. The study employed a specialized instrumentation system andcomputational algorithm. The results revealed no significant difference among the stocking densities under thermoneutralconditions with regard to the following: daily feed intake (97 to 101 g/hen, p = 0.37), daily feeding time per hen (3.0 to4.0 h/day, p = 0.32), number of meals ingested per day per cage (117 to 181 meals/day, p = 0.18), meal size (1.6 to2.6 g/meal-hen, p = 0.09), meal duration (174 to 258 s/meal, p = 0.40), ingestion rate (0.47 to 0.77 g/min-hen, p = 0.06),and number of hens feeding per meal (1.9 to 2.0 hens/meal, p = 0.72). However, there was a trend that hens under the 465 cm2(72 in.2) stocking density displayed a greater meal size and ingestion rate. A field-scale study further investigating the effectsof conventional vs. newly recommended (and voluntarily adopted) stocking densities on commercial egg layers seemswarranted.