The effects of short term enrichment on learning in chickens from a laying strain (Gallus gallus domesticus)

Rearing and housing systems can have substantial effects on behaviour and physiology in domestic animals. In laying hens, several housing systems with different degrees of enrichment are in commercial use. Here, we tested effects of short term enrichment of housing conditions on the exploration and learning performance in 6 weeks old chickens of a laying hen strain. Subjects were either kept in a litter floor system indoors or in an identical compartment but with additional access to an outdoor free range 1 week prior to the experiments. Subjects from both treatment groups then were tested for exploration and learning performance in a Y-maze. The short term enrichment resulted in a significant difference in learning behaviour and exploratory behaviour. Subjects from enriched conditions with free range access left the start-box faster (p = 0.030), were better in learning the Y-maze task (p = 0.033), and made fewer initial mistakes (p = 0.012) in the Y-maze than subjects from litter floor without free range access. Thus, subjects from the enriched group explored the Y-maze faster, and had a better and faster learning performance. However, in a memory test conducted after the training phases we did not find any differences between groups. The results show that short term enrichment of housing conditions in chickens can have positive immediate effects on behaviour by reducing behaviours that are likely to reflect fearfulness and by positively affecting learning performance.