Fig 2. Layout of experimental pens.
The barn contained home pens (basic or enriched) and reward pens (basic or enriched). Basic pens (2 m2 per calf) were bedded with river stones. Enriched pens (5 m2 per calf) were bedded with wood shavings and contained 3 ‘enrichment’ items: automated grooming brush, hanging manila rope, and pile of straw. All home pens contained meal, hay and water feeders. Home pens were linked with an alleyway to the reward pen during conditioning, testing and contrast phases for 30 min per day.