Stocking density is a crucial environmental factor in livestock and poultry production,serving as a key indicator for assessing animal welfare.Excessive stocking density has the potential to alter both the housing environment and animal behavior,ultimately exerting a detrimental impact on the homeostasis of animals,this negative influence manifests through various channels,such as disruptions in hormone secretion,antioxidant capacity,animal behavior,nutrition metabolism,and intestinal function.These disruptions stem from the heightened stress response in animals might cause an increased incidence of animal diseases and a decline in production performance.This article primarily summarizes the effects of stocking density on animal production performance and health status from three aspects:housing environment,animal behavior and stress response.The objective is to provide scientific evidence for the rational design and utilization of livestock and poultry housing and facilities to facilitate the high-quality development of animal farming.[Chinese Journal of Animal Nutrition,2024,36(1):141-150]