Foraging crumbles reduce severe aggression in laboratory mice

Providing foraging crumbles in mouse cages is one method used in efforts to reduce aggression in laboratory mice. However, no studies have yet examined the effects of this procedure. Therefore, we investigated whether foraging crumbles decrease aggression, increase aggression, or do not affect the aggression observed in male laboratory mice. Results indicated that foraging crumbles were associated with a decrease in severe aggression, particularly that which caused injury. At the 100-day mark, to ensure the crumbles would not affect experimentation and to elucidate the behavioral effect of isolation on mice, four behavioral assays were run. Crumbles did not significantly interfere with the mice's cognitive, anxiety, or circadian rhythm performances.