【正文】 , laying rate drop, a few chicken death. ③ cannibalism. Rearing density (crowding stress), the high temperature (heat stress), the light is too strong (light stress), skin trauma and hemorrhage (stress), scabies or other external parasites (such as itching stress) stress stimulation, can cause stress reaction of pecking。Vitamin E and stress response Stress (stress) refers to the sum of nonspecific response to external or internal very stimuli, caused by stress factors known as stress factors or stressors (stressor). The mobilization of body tissues and organs to deal with, to adapt to the series of responses to stress stimuli showed that general adaptation syndrome (GAS). It is organized as follows: ① the physiological changes of adrenocorticotropic hormone (ACTH) production and increased release of, anterior pituitary enlargement. ② adrenal hyperplasia enlargement. ③ due to increased release of corticosterone and adrenal cholesterol secretion decreased. ④ poult reaction are most sensitive to tissue lymph, thymus, bursa of Fabricius and spleen atrophy。 adult chicken because of the influence of gonadal steroids, only the bursal atrophy. The white blood cell changes, showed lymphopenia, heterophils increased. Increase the blood concentration of citric acid. The growth retardation, decreased body weight. The modern intensive livestock production, automation, in order to maximize the level of livestock and poultry production, increase economic efficiency, to livestock and poultry as production machine. The production process and technical measures adopted are often contrary to the animal39。 protein, vitamin, mineral deficiency nutritional deficiency of cannibalism is a stress response. The clinical manifestations of feather pecking, pecking anal, peck peck, peck toe, meat eggs. ④ you disease. Chicken every day within 2h after the onset of disease, call you. You are chicken to the nest on time, so when the dim and dark house, chicken on a particularly intense, sharp heap, trampling each other, extrusion stress lethal. The muscular stomach injury. Muscle of gastric mucosa erosion or ulcer of the occurrence of chicken. 2, 3 chronic stress syndrome By the stress intensity of the longterm repeated stimulation. For example, the lack of nutrition, petition among individuals, raising no rules, and hunger and satiety, Sherwin sometimes hot and sometimes cold, bacterial, fungal infection, the body continues to make adaptation efforts, forming the cumulative effect of adverse effect of chicken, appetite, causing growth retardation, weight reduction, laying rate drop, the hatching rate. Weakened immune response and defense capabilities, easy to secondary infection of other diseases. 3. Stress damage of chicken Normal chicken has the ability to cope with stress from damage, but this ability is limited. The cumulative effect of stress factor or stress beyond protecting threshold, will change from the physiological process for the pathological process. Endanger mainly have the following aspects. performance Stress, protein, carbohydrate, fat and increased catabolism, produce more energy to meet the immediate needs, such as heat, accelerated breathing, heartbeat, and fled, and these nutrients for growth, the original weight, immune function, so the indirect effects of the production performance of chickens, performance poult dysplasia, survival rate is low。 poultry growth, body weight decreased, the meat quality is poor, low feed reward. 3, 2 produce stress syndrome Manifestations of renal cortical hypertrophy, lassitude, rapid heartbeat, high