Aggression and injurious behaviors, including aggressive pecking, feather pecking, vent pecking, and cannibalistic pecking, pose significant health, welfare, and production challenges for laying hens and the global poultry industry. Despite the technological advancements in poultry farming practices, injurious behaviors occur in all the current housing systems. Evidence from human and laboratory mammalian studies suggests that early-life stress may impair gut microbial development and affect gut-brain axis signaling through changes in gut permeability and inflammatory pathways, resulting in neuroinflammation. As a consequence, brain damage causes mental and emotional disorders with abnormal behaviors. Therefore, intervening for maladaptive social behaviors has become a critical topic in various animals including chickens. Despite continuously evolving the outcomes of the microbiota-gut-brain axis interplay, whether similar mechanisms contribute to maladaptive or injurious behaviors in chickens remains an important area for further investigation. The reviewed issues provide an exhaustive scientific analysis of the activation of cecal microbiota transplantation in poultry and describe a potential that injurious behaviors in chickens can be reduced by modification of their gut microbiota profiles and brain serotonergic activity. The outcomes provide a novel insight into developing an intervention strategy for preventing or inhibiting injurious behaviors in chickens. To fully test the strategy, a comprehensive study is required to further explore the signaling mechanisms of cecal microbiota transplantation in injurious behaviors and its scope of application, especially in laying hens.
