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 posit ion in one or other of the symmetrical halves of the home box was noted at each 32 visual scans carried out every day. Cumulative sightings in each ha lf were calculated across the first 5 days to establish the least preferred half. Three 'enrichment' objects were than placed in the least preferred h alf 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 appare nt. The strong side preferences shown by the chicks before the introduction of enrichment stimuli, and their transitory neophobia, sound important cau tionary notes for the design and assessment of husbandry and environmental enrichment procedures.