THE INFLUENCE OF HORMONES ON 



THE SEXUAL BEHAVIOR OF 



DOMESTIC FOWL* 



Introduction 



IN AN AiTEMPT to analyze the results obtained from a study on the sexual be- 

 ha\ior of intersexual males produced by the injection of estrogens into 

 incubating eggs (Domm and Davis'), a series of experiments was begun to de- 

 termine the effect of androgens and estrogen^ on the behavior of the do- 

 mestic fowl (Davis and Domm"). In the above investigation it was found that 

 males in which one or both gonads were ovotestes showed various degrees of 

 masculine behavior which roughly coincided with the degree of masculinity 

 of the plumage. The plumage in turn is known to be an excellent indicator of 

 the relative proportions of testicular and ovarian components comprising the 

 gonad (Domnr). In brief, this study showed that males in which the plumage 

 was essentially normal behaved in a definitely masculine manner while those in 

 which the plumage was female, or nearly so, behaved in an essentially neutral 

 manner. Gradations in behavior between these extremes were encountered. 

 The observations to be discussed in this paper represent the beginning of an 

 analysis of the function of certain hormones in the behavior of the fowl. Ex- 

 periments designed to analyze the behavior of animals must necessarily be 

 extensive because of the difficulty in isolating the numerous factors controlling 

 behavior. For this reason it was considered desirable to conduct an initial series 

 of general experiments, leaving the details to a subsequent, more extensive 

 study. Therefore, the experiments reported at this time must be considered 

 as an analysis of the general responses of capons and bilaterally ovariectomized 

 poulards to androgens and estrogens; further refinements, such as the minimal 

 amount of hormone necessary to initiate a particular response, the effects of 

 learning or conditioning, etc., are reserved for a future time. Some incidental 

 experiments upon males and sinistrally ovariectomized poidards are also con- 

 sidered. 



Materials and Methods 



The brown Leghorn, a highly dimorphic breed of domestic fowl, was used 

 throughout the experiments. The birds were kept in large pens at the Whit- 

 man Laboratory poultry house and fed a standard ration of wet mash, dry 

 mash, corn and greens, etc. (for details see Davis and Domm*). 



The experiments consisted of exposing the injected capons, roosters, and 



* This investigation was aided by a grant from the Dr. Wallace C. and Clara A. Abbott 

 Memorial Fund of The University of Chicago. Grateful acknowledgment is made to Dr. 

 Erwin Sch\\enk of the Schering Corporation for the testosterone propionate and a-estradiol 

 (Progynon-B) and to Dr. J. A. Morrell of Squibb and Sons lor the stilbestrol used in these 

 experiments. 



