1^2 Hormones and the Behavior of Fowl 



poulards to one or more of three stimulus situations. Depending upon the type 

 of injection, the bird was exposed to a normal rooster, to a normal female, or 

 to a dummy. In all cases possible the bird was tested in its own pen so that it 

 was familiar with its surroundings. The normal roosters used were healthy 

 individuals of the same age as the capons and in the prime of sexual vigor, 

 except as mentioned in one experiment. The females also were normal vigor- 

 ous birds which were good layers and receptive. The dummy was a normal 

 hen stuffed and mounted in the pose of invitation to copulation (squatting). 

 The routine experiment consisted of placing the test bird (rooster, hen, or 

 dummy) in the empty pen and then introducing the experimental bird. 

 Although the observer stood in the pen at a distance of a few feet, it is certain 

 that his presence had no effect on the behavior. The reader is referred to the 

 paper by Davis and Domm* for a detailed description of the normal sexual 

 behavior of the fowl. 



The birds were injected daily at about 11:00 a.m. In a few days they be- 

 came tame, and readily submitted to the treatment so that there is little if any 

 possibility that the ordeal of injection influenced their behavior. The reader 

 is referred to the table which gives a summary of pertinent data. 



Observations 



The series of injections was designed to indicate the action of androgens and 

 estrogens in controlling behavior. Since in general the end result is the im- 

 portant point, description of the developmental stages will be omitted for the 

 most part in this paper. 



1. The Effect of Androgen in the Capon. Two capons under the influence of 

 testosterone propionate copulated repeatedly with both the dummy and 

 females. Bird 149M was first observed to crow on the eleventh day and to tread 

 on the fourteenth day of injection. Bird 153RM copulated first on the seventh 

 day and crowed on the tenth. Since the birds were not under continuous ob- 

 servation it is quite likely that they crowed several days before the dates men- 

 tioned.* A third bird, 143R, which received the lowest dosage, was very excitable 

 during the experiments and this excitability had not noticeably vanished six 

 months after injections were stopped. He never copulated perfectly although, 

 in contrast to a normal capon, he perceived the dummy. Our evidence is not 

 sufficient at present to state that the dosage received in this case is below the 

 threshold necessary for copulation. 



2. The Effect of Estrogens m the Capon. All three capons copulated under 

 the influence of a-estradiol (Progynon-B). The action was brief but complete; 

 wing-fluttering and movements of tail and cloaca were typical. The birds 

 getting the higher dosages (149M and 153RM) mounted, although weakly, on 

 the sixteenth day (Oct. 7) of injection. Bird 170Y mounted two days later. How- 

 ever, these birds, when compared with the testosterone-treated individuals, did 



* We have since observed crowing in 48 hours and treading within 90 hours in capons re- 

 ceiving daily injections of testosterone. 



