♦Represents retests 



a commercial hatchery and infection is detected in the breeding flock, the supply- 

 ing of hatching eggs is immediately discontinued, according to official regulations. 

 No fiock known to be infected should supply hatching eggs or chicks. If "breaks" 

 are to be prevented or kept at a low level, every breeder should exercise the 

 greatest vigilance in keeping out infection that may enter through the many 

 possible channels. The following nteasufes should be put into practice by flock 

 owners if they expect to establish and maintain pullorum-free flocks. 



1. All the birds on the premises should be tested each year. 



2. If infection is present, the entire flock should be retested within four to six 

 weeks until a negative report is obtained, provided the value of the birds justifies 

 the expenditure. 



