A Study of the Establishment of Social Hierarchy in Erh-Mei Chicken, Beijing Fatty Chicken, Chinese Silky Chicken and NCHU Selected Taiwan Country Chickens and their Fear Responses

• Main Authors: Chen-Hao Wu, 吳振豪
• Other Authors: 李淵百
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/23325884262068041608

碩士 === 國立中興大學 === 動物科學系所 === 102 === Chickens use their beak to fight for their rank in group. It is called the social status, and also “peck order”. The establishment of social hierarchy is important for chickens to maintain the peaceful living in group to reduce the incidence of conflicts between chickens that incur a greater expenditure of energy. In commercial process, chickens encounter many changes including the establishment of social hierarchy, change of environment, feed composition and so on. They show physiological and behavioral fear responses when facing changes. In order to reduce the stress that caused by fear, chickens will change their genetics, physiology and behaviors to adapt them. According to previous researches, many factors influenced the establishment of social status and fear responses. For example, breed, selection, morphology, gender and so on. The aims of my research was to discuss the difference of agonistic behaviors and the establishment of social hierarchy in rearing period and fear responses between selected strains (B and S strain) and conserved (Erh-Mei Chicken, Beijing Fatty Chicken and Chinese Silky Chicken) breeds.My research divided into two parts, first observed the agonistic behaviors and the establishment of social hierarchy in rearing period. The second was the fear tests including novel object test, tonic immobility test and pen plus human test in laying period for each chicken. The first part of results showed that in sex intermingled rearing method, the establishment of social order was mainly among males. S strain recorded the most frequency of agonistic interactions, and lowest was Beijing Fatty chicken. Erh-Mei chicken completed the dominant-subordinate relationship at 10 weeks of age, and other breeds completed during 11-12 weeks of age. The frequency of peck order violation was no significant difference among five breeds. In the analysis of the relationship between body weight, sexual maturity and social order, only B strain and Chinese Silky were found significant positive correlation. The results of fear tests showd that Silky had lowest score in novel object test.Selected strains had lower fear response in TI test, but big body size B strain was more fearful than S strain. No significant difference was found among conserved breeds. S strain showed active and lower fear response in pen plus human test. Erh-Mei chicken had longer latency of vocalize but shorter latency of step. It may cause by specific of breed. The cock of B strain and pullet of Silky was more fearful than other breeds. Three fear tests invoked different stimuli that may induced different fear response among breeds. In the analysis of the relationship between fear tests and social order was found little significant correlation. It may cause by environment, breed and other factors. Above all, selected breeds were precocious, selected and conserved breeds only had little difference for the age to complete in establishment of social hierarchy. It could be the large flock size in the pen complicated the establishment of social hierarchy. The fear responses of selected chicken influenced by body size, and conserved breeds influenced by the difference of morphological characteristics. S strain had the most frequency of agonistic interaction. To improve animal welfare and economical benefit, it should be raised with an effective management to reduce agonistic interaction that incur physical damage.