Can 'Environmental Enrichment' Affect Domestic Chickens' Preferences for One Half of an Otherwise Symmetrical Home Cage?
Chickens were reared in pairs in wooden boxes from 1 to 10 days of age. One chick from each pair was marked to facilitate identification and its position in one or other of the symmetrical halves of the home box was noted at each of 32 visual scans carried out every day. Cumulative
sightings in each half were calculated across the first 5 days to establish the least preferred half. Three 'enrichment' objects were then placed in the least preferred half of each box on day 6. The chicks' positions were again recorded at each of 32 scans on 5 consecutive days. The enrichment
objects were avoided on day 6 but such neophobia waned within 24h and a weak, non-significant trend for enrichment to increase usage of the least preferred half became apparent. The strong side preferences shown by the chicks before the introduction of enrichment stimuli, and their transitory
neophobia, sound important cautionary notes for the design and assessment of husbandry and environmental enrichment procedures.