172 



COMMERCIAL POULTRY RAISING 



of the nest; as she passes the point where the door is hinged to 

 the treadle, her weight causes it to fall, which pulls up the door 

 behind her, as shown in lower view. It is then impossible for the 

 hen to leave the nest or for other hens to enter, until the atten- 



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(California Experiment Station) 

 Fig. 120. — Plans for a single-compartment trap nest. 



dant resets the trap by depressing the door to its original hori- 

 zontal position. The operation is extremely simple, consists of 

 but one movement, with no triggers or other locking devices to 

 adjust. 



When a hen has laid an egg and desires to leave the nest, she 



