Experiments were conducted to test whether social experience could influence the ability of chickens to balance their diet by choosing between two foods, one rich in energy and the other rich in proteins. A relationship between social structure and feeding behaviour was apparent when broiler and layer chicks were compared. Young broilers placed with other birds, even inexperienced ones, showed higher growth rates than did isolated broilers. Young layers showed a less stable group structure and did not have a higher growth rate than isolated birds. Older layers in groups showed clearer social structures. A social structure based on leadership seems characteristic of chicken groups, even those consisting of very young birds.