Poultry have been observed to suppress feeding when a new diet or a new batch of the same diet is first presented. This transitory phase seems to be related to the birds’ inability to recognize the food as edible or they classify it as ‘unknown’. The objective of this study was to determine if cognitive processes are involved in food recognition and rejection. Sixteen groups of broiler chicks were fed a low quality feed in their home pens and were trained to run a maze to gain access to a high quality feed. When training was completed, eight of the groups were given a low quality diet in the trough at the end of the maze (the same diet they received in their home pen). The other eight groups continued to receive the high quality diet. The authors predicted that time to reach the end of the maze would decrease significantly for the birds given the low quality diet. The birds that received the low-quality diet did not immediately decrease the time they took to complete the maze (as would be expected if the birds used a cognitive comparison). However, after four day, the experimental group was significantly slower to reach the end of the maze compared to the control group. On the day of the change, the birds displayed behaviour that could be indicative of frustration. The experimental birds showed more scratching and hurried movements and less pecking at feed. Food consumption was also less after the change onward for the experimental birds. The authors concluded that there was no definitive evidence for the presence of a cognitive representation of food. They suggest that this may have been due in part to testing groups as opposed to individual birds, and perception of food quality. Behaviours that may indicate frustration in the experimental birds suggested that a cognitive expectation might have been present.