The impact of early structural enrichment on spatial cognition in layer chicks

The aim of the study was to determine whether early access to elevated structures affects spatial navigational abilities. Ninety six day-old chicks were reared in 16 pens. Eight pens were provided with A-frame perches with an attached platform and a ramp. Eight pens had no elevated structures. At 14-15 days of age 48 chicks were tested in a battery of navigational tasks: a detour test, jump test and rotated floor test (RFT). The remaining 48 chicks received the same tests at 28-29 days of age. Chicks reared with elevated structures were faster at completing the detour test (P=0.045). Older chicks were more likely to turn left in the detour test (p=0.013) and were more successful in the jump test (69% vs 31% completion, p=0.001). There was no treatment effect on use of intra or extra maze cues in the RFT, but the proportion of chicks using intra-maze cues declined between the first (0.76) and second (0.43) repeat of the RFT (p=0.038), particularly for chicks reared with elevated structures. We conclude that bird age or developmental stage may have a predominant influence on spatial navigation and physical ability, but early experience of elevated structures had some mediating effects which require further investigation.