CONSTRUCT-VALIDATION OF BEHAVIORAL INDEXES OF ISOLATION STRESS AND INFLAMMATORY NOCICEPTION IN YOUNG DOMESTIC-FOWL

Isolation from conspecifics can elicit a variety of behavioral respons es in young domestic fowl that include increased vocalizations (VOC), ventral recumbency posturing (VRP), hypoalgesia, and hyperthermia. Dur ing tests of acute inflammatory nociception, chicks not only display s everal pain-related behaviors (i.e., footpecks and lifts), but also VO C and VRP. However, systematic evaluation of whether these behaviors r eflect converging indices of stress and nociception remains to be cond ucted. In two separate experiments, 7-day-old chicks received intrapla ntar formalin (0.05%) or saline (0.05 ml) and were placed in sound-att enuating chambers with or without two conspecifics for a 3 min observa tion period. The following measures were recorded: VOC, footlift frequ ency (LFT), and duration (DUR, Experiment 2 only), pecks (PKS), ventra l recumbency latency (VRL), body temperature (BTMP), and body weight ( WGT). Principal component analyses revealed the presence of two obliqu e and nonmonotonically related components, one consisting of pain-rela ted measures (i.e., LFT, DUR, and PKS) and the other consisting of str ess-related measures (VOC, VRL, and BTMP). A third component, consisti ng of BTMP and WGT ostensibly reflects maturational variability in the rmoregulatory capability. These findings support the construct validit y of these behavioral indices of isolation stress and inflammatory noc iception and are consistent with the notion of stress effects on nocic eptive processing.