A cognitive approach to better understand foraging strategies of the adult domestic hen

Foraging is known to be one of the most important activities in the behavioral budget of chickens. However, how these animals adapt different foraging strategies to diverse environmental variations is currently poorly understood. To gain further insight into this matter, in the present study, hens were submitted to the sloped-tubes task. In this task, the experimenter can manipulate the information that enables the hens to find a food reward (visible or not), placed in one of two hollow tubes. First, 12 hens were tested under free-choice conditions (no penalty for exhaustive searching in both tubes). Under these conditions, the hens adopted a non-random, side-biased strategy when the food location was not directly visible. Then, we divided the hens in two cohorts of equal size to study deeper the hens' foraging strategy when faced (1) with a different container, or (2) with a restrictive environmental constraint under forced-choice conditions (no food reward if the unbaited tube is visited first). This latter constraint increased the risk of the hen not receiving food. A change in the containers didn't modify the search behavior of the hens. However, in forced-choice conditions when the location of the food was not directly visible, four out of six hens learned to choose by exclusion. We conclude that hens can selectively adapt their foraging strategy to the point of adopting an exclusion performance, depending on available information and environmental constraints (high or low risk).