Incentive value learning in domestic hens

The present experiment investigated whether domestic hens (Gallus domesticus) assign different incentive values to novel food depending on their deprivation state when they encounter this novel food. Firstly, hens were trained to search under wood shavings in a food dish to find a small amount of a novel food. Half of the hens were then presented with the novel food while food deprived, and the other half were presented to it while sated. In the test, all hens were food deprived, and given access to the food dish used in the first stage, filled with shavings but without food. Hens that had experienced the food while deprived spent more time on food-related behaviours in and at the dish than did hens that had not (pecking at dish, Median 63 vs. 37, p < 0.05). These results indicate that the first group had assigned a higher value to the novel food. The results show for the first time that incentive value learning occurs in domestic hens. This implies that care must be taken when designing choice tests to take into account the animal’s motivational state when it previously encountered the resources being studied.