distrilnit ion of eggs, baby chicks, and adult slock. The flock owners of puliorum- 

 clean flocks are justified in priding themselves on the fact that they have so 

 conclusively demonstrated that they were capable of establishing and maintaining 

 flocks free of this disease. Furthermore, the owners of pullorum-clean flocks 

 have realized a mental satisfaction, as well as financial saving, as the result of no 

 losses suffered from pullorum infection. 



The percentage of flock owners who tested all the birds on the premises has 

 increased from 52.6 in 1932-33 to 66.8 in 1933-34. The soundness of testing all 

 birds on the premises cannot be ignored, because the exact status of a flock cannot 

 be determined with any degree of certainty by testing only part of the birds. 



Appearance of Infection in Flocks Previously Negative 



During the 1933-34 season infected birds were found in 12 flocks that had been 

 negative for one or more years. Table 3 shows that in all but three of these 

 flocks the percentage of reactors was less than one. The source of the infection 



Table 3. — Infected Flocks With a Previous Negative Testing History 



Explanation 



4 1 790 689 0.29 Custom hatching and purchase of questi 



able stock 



5 3 1,382 1,382 0.87 Purchase of eggs from questionable stock 



1.010 *1,015 0.00 



6 7 2,788 2,788 0.11 Unsatisfactory 



2,791 *491 0.00 



7 5 1,810 1,5G0 0.38 Purchased eggs from an infected source 



1,494 1,488 0.00 



8 3 872 321 10.59 Purchased chicks from untested source 



711 *261 1.15 



9 2 1,468 1,168 0.68 Practices custom hatching 



1,431 271 2.21 



10 4 1,660 1,510 0.31 No information 



1,447 *1,3.56 0.00 



11 4 1,310 1,310 0,23 Unsatisfactory 



12 3 1,295 1,295 0.08 Unsatisfactory 



