COMPLETE SEX-TRANSFORMATION IN 

 THE DOMESTIC FOWL 



F. A. E. Crew 

 Animal Breeding Research Department. Edinhurgli University, Scotland 



IN FEBRUARY. 1931, a Buff 

 Orpington was brought to thi; 

 Department. During the preced- 

 ing January its owner had decided that 

 there was far too much crowing for a 

 city pen, and she had had the male 

 bird killed. Shortly after this it was 

 noticed that a great deal of crowing 

 was still coming either from the pen 

 or from somewhere nearby, and at 

 length it was found that one of the 

 hens was responsible for the noise. 

 This bird was three and one-half years 

 old, pure-bred, and had ceased to lay 

 in the late summer of 1920. She had 

 raised several broods of her own chick- 

 ens. On her arrival here she exhibited 

 the classical signs of early ovarian dis- 

 ease, the head- furnishings were larger 

 than those of a typical hen of her 

 breed, the left spur was three milli- 

 meters, the right one two millimeters 

 in length. The plumage was entirely 

 henny. She crowed persistently, but as 

 one practising, and her sexual behavior 

 was completely indifferent. 



In April, 1931, the vascular tissue of 

 the head had become markedly tur- 

 gescent so that the eye appeared to be 

 deepset amid flaming red congested 

 flesh; and the comb, wattles and 

 spurs had progressively increased in 

 size. The bird had begun to moult 

 irregularly, and was suffering from an 

 intractible diarrhoea, losing weight and 

 seeking solitude. By October she had 

 become completely cocky- feathered, 

 though she could never retain her tail 

 sickles. The spurs were now one centi- 

 meter in length and the legs had as- 

 sumed the red tinge which character- 

 izes the male of her breed. She was 

 carefully nursed through the winter 

 and by February, 1933, she had over- 

 come the more urgentlv dangerous 



symptoms, was crowing lustily with a 

 challenging note, and was readily at- 

 tracted by hens, which, would squat at 

 her approach, the sexual act being per- 

 formed. "He" fought with every male 

 in the yard and was gently courteous 

 to hens. In fact, only by one with an 

 intimate knowledge of poultry, or by 

 placing it alongside a "real" male, 

 could it be told that this bird was dif- 

 ferent from a typical male. Its stance 

 was different from that of a cock, for 

 the bird was shorter on its legs and 

 these were set at a different angle with 

 the body. 



On February third, the bird was 

 penned with a virginal Buff Orpington 

 far removed from all other birds. This 

 hen was laying, and the eggs which she 

 had laid during the previous fortnight 

 were incubated and found to be unfer- 

 tilized. Her mate performed the 

 sexual act regularly and fluid passed 

 into the cloaca of the hen was 

 withdrawn and examined. On April 

 33rd a few living spermatozoa were 

 identified. On June sixteenth the hen 

 became broody and was set upon nine 

 of her own eggs laid during the pre- 

 vious eighteen days. On July seventh 

 two chickens were hatched ; the other 

 eggs were clear. By this time the father 

 of these chickens had again become 

 seriously ill and a large tumor could be 

 felt cephaled to and discreet from the 

 gizzard. The bird began to lose 

 weight rapidly and suffered from seri- 

 ous diarrhoea. On December twenty-' 

 ninth "he" fell into an opened drain 

 and was drowned. At the time of its 

 death its comb measured four centi- 

 meters at its highest point, the right 

 spur was four centimeters, the left five 

 centimeters long, the scanty plumage 

 was entirelv cockv. 



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