344 ANIMAL AGGREGATIONS 



Ebbe (1922) in his analysis of the intragroup relationships shown by 

 a flock of domestic hens. Such a group forms not a closed but an 

 open society; that is, new members are admitted as occasion de- 

 mands. The flock is organized by what Schjelderup-Ebbe calls the 

 "peck-right," or the "peck-order." 



The rank of individuals within the group is indicated by their re- 

 action when another member pecks or threatens to peck them. A 

 given hen will submit to pecking by certain individuals without 

 expressing resentment, and will in turn have the right to treat others 

 similarly without their showing protest reactions. Hens with this 

 power are said to have the "peck-right" over those submitting to 

 the pecking. The "peck-order" decides which birds may peck others 

 without being pecked in return. The ranking is determined by com- 

 bat or by passive submission. A newcomer can win a position above 

 the bottom of the peck-order only by fighting. 



Sometimes the peck-order within the flock is in a simple con- 

 tinuous series, thus: A pecks B; B pecks C; C pecks D; and so on 

 down to the humblest member of the flock. But it may happen that 

 the peck-order is more confused. A may peck B; B may peck C; 

 and still C may have the peck-right over A. Frequently, strong 

 hens are pecked by weaker ones. This is due to the fact that young 

 ones are attacked by older members of the flock, newcomers by 

 old-timers, sick by healthy; and the order, once established, tends 

 to remain permanent. A revolt or a fight may either change or 

 confirm a previously existing peck-order. If the original order was 

 accepted passively rather than as the result of a combat, a rebellion 

 is more likely to occur. A hen revolting against a previously recog- 

 nized superior fights less fiercely than at other times. This indi- 

 cates a psychic obstacle to such an attack. Once a hen has accepted 

 an inferior position, it is more difficult for her to return to superiority 

 than if she had fought for the position at the start. 



Position in the peck-order is associated with certain behavior 

 traits. The hen which is entitled to peck all others is usually the 

 least malicious, and a threatening note usuafly suffices for a peck. 

 A hen low in the scale is usually cruel to the remaining hens. Katz 



