Jones R B, Harvey S
AFRC Institute of Animal Physiology and Genetics Research, Roslin, Midlothian, EH25 9PS, Scotland.
The Wolfson Institute, University of Hull, Hull, HU6 7RX, N. Humberside, England; Present address: Department of Physiology, Faculty of Medicine, University of Alberta, Edmonton, Canada.
Behav Processes. 1987 Jun;14(3):291-303. doi: 10.1016/0376-6357(87)90075-1.
Disruption of an animal's social environment often causes distress and the effects of systematic reductions in group size on the behaviour and plasma corticosterone concentrations of domestic chicks were assessed in Experiment 1. Because this procedure also exposed the chicks to repeated disturbance by the experimenter, the behavioural and adrenocortical consequences of sequential capture and replacement of social companions were examined in Experiment 2. Female White Leghorn chicks were housed in groups of eight and remained undisturbed in both experiments until testing began at 14 d of age. Systematic reduction of group size was accompanied by both endocrine and behavioural modifications in Experiment 1. Thus, plasma corticosterone levels rose, feeding, drinking, preening and pecking at the environment gradually ceased whereas defaecation, ambulation, jumping and peeping became increasingly prevalent. These modifications were generally abrupt rather than progressive. Endocrine changes preceded behavioural ones which generally became evident when only two or fewer chicks remained. Conversely, the sequential capture and temporary removal of chicks from established groups in Experiment 2 elicited no significant effects in their uncaptured companions. The results are discussed in terms of social disruption, disturbance of companions by the experimenter, social motivation, predator evasion, individual recognition and fear.
破坏动物的社会环境通常会导致其痛苦，在实验1中评估了系统性减少群体规模对家鸡行为和血浆皮质酮浓度的影响。由于该操作也使雏鸡受到实验者的反复干扰，因此在实验2中研究了依次捕捉和替换社会同伴对行为和肾上腺皮质的影响。雌性白来航雏鸡以每组八只的方式饲养，在两个实验中，直到14日龄开始测试前都未受到干扰。在实验1中，系统性减少群体规模伴随着内分泌和行为的改变。因此，血浆皮质酮水平升高，进食、饮水、梳理羽毛和啄环境的行为逐渐停止，而排便、行走、跳跃和鸣叫则变得越来越普遍。这些改变通常是突然的，而非渐进的。内分泌变化先于行为变化，行为变化通常在只剩下两只或更少雏鸡时才变得明显。相反，在实验2中，从已建立的群体中依次捕捉并暂时移走雏鸡，对未被捕捉的同伴没有产生显著影响。将根据社会破坏、实验者对同伴的干扰、社会动机、捕食者躲避、个体识别和恐惧等方面对结果进行讨论。
