Environmental enrichment (Young, 2003; Mason et al., 2007)

• Environmental enrichment is the practice of improving captive or domestic animal environments to enhance welfare.
• Aim: promote natural behavior, reduce stress, and prevent abnormal behaviors (stereotypies).
• Essential in zoos, farms, laboratories, and shelters to meet behavioral, physical, and mental needs.

Types of Environmental Enrichment

a) Physical / Structural Enrichment

• Modifying enclosure design to provide perches, climbing structures, burrows, hiding places, or platforms.
• Encourages exercise, exploration, and natural postures.
• Example: climbing frames for primates, perches for birds, rooting areas for pigs.

b) Social Enrichment

• Housing animals with conspecifics or compatible species to allow social interactions.
• Reduces isolation stress and encourages natural social behaviors.
• Example: group housing of hens or calves, pair housing of laboratory rodents.

c) Nutritional / Feeding Enrichment

• Presenting food in ways that encourage foraging, hunting, or manipulation.
• Examples: puzzle feeders, scatter feeding, or hiding food in straw or substrates.
• Reduces boredom and stereotypic feeding behaviors.

d) Sensory Enrichment

• Stimulates senses (sight, sound, smell, touch, taste).
• Examples: novel scents for carnivores, mirrors for birds, auditory enrichment like natural calls.
• Improves mental stimulation and reduces stress.

e) Cognitive / Occupational Enrichment

• Challenges animals mentally to solve problems or perform tasks.
• Examples: mazes, problem-solving feeders, training with positive reinforcement.
• Enhances learning, exploration, and behavioral flexibility.

Benefits of Environmental Enrichment

• Encourages natural behavior expression.
• Reduces abnormal or stereotypic behaviors such as pacing, feather pecking, or bar-biting.
• Improves physical fitness, mental stimulation, and overall health.
• Enhances welfare indicators: activity levels, social interactions, and reproductive success.
• In farm animals, enrichment can improve productivity and reduce injuries.

Principles for Effective Enrichment

• Enrichment should be species-specific, reflecting natural history and behavior.
• It should be dynamic, changing over time to maintain novelty.
• Should not compromise safety, health, or management practices.
• Must be practical, cost-effective, and sustainable in long-term husbandry.

Examples in Different Species

• Cattle: Brushes for grooming, straw for foraging, pasture access.
• Pigs: Straw, rooting substrates, toys, social group housing.
• Poultry: Perches, dust baths, pecking blocks, outdoor access.

• Captive wildlife: Puzzle feeders, climbing structures, social groupings, sensory stimuli.
• Laboratory rodents: Nesting materials, tunnels, running wheels.