Genetic Variation in the Crow of Adult Chickens

GENETIC VARIATION IN THE CROW OF ADULT CHICKENS by P. B. SIEGEL, R. E. PHILLIPS and E. F. FOLSOM 1) 2) 3) (Virginia Agricultural Experiment Station, Virginia Polytechnic Institute, Blacksburg, Virginia, USA) (With 3 Figures) (Rec. 25-V-1964) The crow of the cock is well suited to studies of stereotyped, genetically controlled behavior, and numerous workers have investigated aspects of it. The dependence of crowing on sex hormones was indicated by the castra- tion and implantation experiments of BERTHOLD (1849) and extended by HAMILTON (1938) and NoBLE & ZITR1N who initiated precocious crowing by injections of male hormone into young cockerels.