268 RAYMOND PEARL 



together a few leaves on the ground by way of nest. She remains 

 as part of the cock's seraglio until some seven or ten or a dozen 

 eggs have been deposited in the above spot, to which she steal- 

 thily repairs every day, and finally quits her party and retires 

 alone and unseen to perform the duties of incubation." 



In the case of the domestic fowl it has long been known that 

 the brooding instinct could be aborted by proper treatment. 

 This is obviously an important matter when hens are kept for 

 egg production. Since a hen lays no eggs while broody the sooner 

 the desire to " sit " can be overcome the sooner will she be brought 

 back to the profitable performance of her duty as an egg pro- 

 ducer. The usual method adopted for overcoming the tendency 

 to brood is to confine the bird in a small coop with a slatted or 

 bare board floor. Usually in a comparatively short time the 

 tendency towards broodiness will disappear and if the bird is 

 then put back under normal conditions she will again commence 

 to lay, and may continue to do so for some time before the onset 

 of another spell of broodiness. Just why this treatment should 

 be so effective as it actually is, is not entirely clear. Formerly 

 it was supposed to be necessary to " cool the blood " in order to 

 ' break up a sitter," and the somewhat drastic treatment of 

 dipping the bird in a bucket of ice water was practised. It is 

 probable that the chief factors concerned in producing the good 

 results following confinement in a small coop are (1) that the 

 bare floor and absence of eggs gives no encouragement to the bird 

 to "sit," but on the contrary acts as a set of stimuli strongly 

 antagonistic to this phase of instinctive behavior and (2) that 

 the sudden change of conditions acts to upset the more or less 

 delicately balanced physiological and psychical condition which 

 characterizes the broody bird. 



The instinct of brooding varies greatly in different breeds of 

 domestic poultry. Some breeds — notably those classed by 

 poultrymen as Mediterranean — have the instinct very slightly 

 developed. Others — for example certain of the Asiatic breeds — 

 go to the other extreme and have the instinct very strongly 

 developed. The so-called American breeds, on the whole, 

 occupy an intermediate position in this regard. With them the 

 usual or normal course of events relative to broodiness is as 

 follows . 



