A deficient serotonergic system is associated with psychopathological behaviors in various species, among which, feather pecking (FP) in chickens. Deficiency in the serotonergic system can predispose birds to develop FP, while the serotonergic system is affected in birds that feather peck. Serotonin (5-HT) can further influence dopamine (DA) activity. Lines with high FP tendency generally have low central 5-HT and DA turnovers at a young age, but high turnovers at an adult age in brain areas involved in somato-motor regulation and goal-directed behavior. Agonizing 5-HT1A and 5-HT1B receptors increases FP, while antagonizing D2 receptor reduces FP. Genetic associations exist between FP, 5-HT1A and 5-HT1B receptor functioning and metabolism of 5-HT and DA. Birds with deficient functioning of the somatodendritic 5-HT1A autoreceptor and 5-HT metabolism appear predisposed to develop FP. Birds which feather peck often eat feathers, have low whole-blood 5-HT, different gut-microbiota composition and immune competence compared to non-peckers. FP and feather eating likely affect the interaction between gut microbiota, immune system and serotonergic system, but this needs further investigation.

血清素能系统不足与各种物种的心理病理行为有关，其中包括鸡的啄羽（FP）。血清素能系统的缺乏会促使鸟类发展FP，而羽毛素啄的鸟的血清素能系统受到影响。5-羟色胺（5-HT）可以进一步影响多巴胺（DA）的活性。具有高FP倾向的品系在年轻时通常具有较低的中心5-HT和DA转换率，但在成年时在涉及体动调节和目标定向行为的大脑区域中，其转换率较高。拮抗5-HT1A和5-HT1B受体可增加FP，而拮抗D2受体可降低FP。FP，5-HT1A和5-HT1B受体功能与5-HT和DA代谢之间存在遗传关联。体树突状5-HT1A自身受体功能不足和5-HT代谢不足的鸟类似乎易患FP。与非啄木鸟相比，羽毛啄木鸟经常吃羽毛，全血5-HT低，肠道菌群组成不同和免疫能力强。FP和吃羽毛可能会影响肠道菌群，免疫系统和血清素能系统之间的相互作用，但这需要进一步研究。