Testicular Size in Roosters – Hayyy Farms

Understanding Rooster Anatomy: The Role of Environmental Factors in Testicular Size (And, is it Linked to Aggression?)

Large rooster standing in grass and looking towards the camera

The belief that some roosters are predisposed to aggression solely due to having large testes is misleading. Research shows that a wide range of environmental factors, including behavior, diet, weight, living space, position within the flock, and access to hens, significantly influence testicular size beyond their genetic baseline. While aggressive behavior often correlates with environmental conditions that promote higher testicular growth, large testicular size should ultimately be viewed as an effect of those environmental conditions, rather than a direct cause of aggression.