Broiler chicks remained undisturbed or were exposed to an acute stressor (mechanical restraint) before measuring tonic immobility and fear responses one hour later (experiment 1). Exposing the birds to the stressor significantly prolonged their tonic immobility response and most likely their underlying fear levels as well. In experiment 2, the response of the undisturbed control chicks and the stressed chicks were assessed by placing them each individually in a runway with a goal box containing either familiar or unfamiliar chicks of the same age. Findings of the study indicated that stressed chicks emerged from the start box sooner and spent a greater amount of time near the stimulus birds, suggesting that exposure to a frightening event increased social reinstatement motivation. Social affiliation was even stronger when the goal box contained familiar chicks rather than strangers, regardless of prior treatment. This indicates that broiler chicks housed in groups of twelve can discriminate between familiar and unfamiliar cagemates when encountered in a novel situation. Therefore, sociality was positively associated with fearfulness and the chicks distinctly showed social discrimination in runway tests. Conclusions stated that fear and the capacity of social recognition in tests of social motivation were important to birds. Recommendations stated that exposure to frightening events before a test should be avoided and the identity of the birds in the runway goal box should be standardized and noted (i.e. familiar or unfamiliar).