Assessment of emotional reactivity, learning and memory in chickens
T-maze & Y-maze
Because little is known about the reliability and validity of behavioral tests for poultry, four different behavioral tests were performed with two different lines of laying hens (Gallus gallus domesticus). In this report only the T-maze test and the Y-maze test are described.
There was performed a T-maze test. Chickens had to choose between one of the two arms of a maze, one being empty, and one containing two conspecifics. Silver Nick chickens visited their conspecifics more in a trial. Silver Nick and Brown Nick chickens made significant progress in the latency of contacting the conspecifics. Silver Nick chickens made more visits to the arm with conspecifics over the five trials.
There was performed a Y-maze test. In this test chickens had to choose the arm containing a food reward. The Silver Nick chickens were faster in eating the mealworms than Brown Nick chickens. Both lines of chickens made significant progress over the six trials in latency of eating a mealworm and frequency of visits to the rewarded arm. The latency of eating the mealworm was shorter for the Silver Nick. Over the trials there was a decline in visits to the empty arm for both lines. The Silver Nick made more correct first choices in the Y-maze than Brown Nick chickens.
The beak of the Brown Nick chickens was trimmed whereas the beak of the Silver Nick chickens was undamaged. So, it is difficult to determine whether the found differences in the behavioral tests were due to strain differences or the negative influence of beak trimming.