INSTINCTS AND HABITS IN CHICKS 5 



Greater freedom of movement was provided for the birds by 

 the use of two cages that were connected with the brooder. For 

 litter, white sand and shredded alfalfa were found satisfactory. 

 Sand is more suitable than ordinary earth where it is desirable 

 to avoid dust. A chick food ' that is regularly on the market 

 served our purposes very well. With the above simple equip- 

 ment the chicks for the experiments were hatched and kept in 

 the animal wing of the laboratory. 



IV. Observations and Experiments 

 A. First Activities 



If one would have the ontogenetic history of a chick, he must 

 begin his study of the development of activity while the chick 

 is still within the egg. A movement of the egg tray was some- 

 times found to be the occasion of a chirp within the egg hours 

 before the shell was chipped. Or, chirping at times occurred 

 so loud that it could be heard distinctly in the room in which 

 the incubator was situated, when the incubator was tightly 

 closed and no external stimuli, such as noises and jars, were 

 noticed. Before the shell w^as broken at any point, a continuous 

 tapping sound could often be heard within the egg, somewhat 

 as if the chick were pecking against the inside of the shell. The 

 movements of chicks just after the shell w^as chipped were 

 observed through the glass door of the incubator and also seen 

 to good advantage when the eggs were removed from the' incu- 

 bator and put in an appropriate receptacle under an electric 

 light. Upon these latter occasions the ragged edges of the egg 

 shell near the beak of the chicken were removed to give a better 

 view of the animal's movements. Upon the observations follow- 

 ing the transfer of a chipped egg to a nest warmed by an electric 

 light, I find the following note : "I broke away much of the shell. 

 After bill of chick was entirely out of reach of the shell, the 

 chick continued to make a sound somewhat like pecking, and 

 that, too, without opening and closing the bill. The ' clicking ' 

 sounds seemed to accompany the rhythmical heaving of the 

 animal, which I took to be breathing. . . . Eyes were 

 open, apparently, as soon as chick had unfolded itself." At 

 the next hatch another chick was observed under an electric 



' Cyphers Chick Food, sold by the Cyphers Incubator Co., Boston, Mass. 



