In the group tested for three or more consecutive years there were 257 flocks, 

 representing 1,011,187 tests, of which 0.0007 percent were positive. Only one 

 flock was classified as positive. The average number of birds per flock was 3,895. 



For all the four groups 338 flocks were tested, representing 1,178,090 birds, 

 and 1,195,159 samples of which 0.004 percent were positive. This is the lowest 

 percentage of reactors ever detected in the testing history of the State. The 326 

 flocks that were 100 percent tested and nonreacting contained 1,159,567 birds or 

 98.43 percent of total birds tested. Three flocks were classified as positive. The 

 average percentage of reactors among these birds was 0.48. 



During the past year, 80 or 21.56 percent of the flocks tested in 1952-53 were 

 not tested. Annual testing of flocks is necessary to determine the pullorum status 

 of flocks in order that infection may be detected before it has an opportunity to 

 become widely disseminated. Each year infection is detected in flocks with a 

 previous pullorum-clean record. Therefore, flock owners should recognize the 

 need for testing. 



APPEARANCE OF INFECTION IN FLOCKS PREVIOUSLY NEGATIVE 



During the past year pullorum "breaks" were observed in only two flocks in 

 contrast to seven the previous year. Both of these flocks had less than 0.5 percent 

 infection. The source of the infection could not be established. 



In table 3 is given the incidence of "breaks" among Massachusetts tested flocks 

 during the past fifteen years. The number of "breaks" this past year is the lowest 

 in the testing history of Massachusetts. It is hoped that no "breaks" will occur in 

 future years and that flock owners, hatcherymen, and other agencies will exercise 

 due care in preventing the introduction of the infection. The precautions fre- 

 quently violated are (1) the purchase of questionable stock, (2) hatching from 

 pullets before they are tested, and (3) hatching of chicks or poults at a hatchery of 

 unknown pullorum status. 



It cannot be emphasized and urged too strongly that one should check the 

 ofiicial pullorum status of all breeding flocks and hatcheries before stock is pur- 

 chased. It is recommended that the flock owners and hatcherymen observe the 

 strictest vigilance against the introduction and spread of the disease. 



The following measures have been found to be effective in establishing and 

 maintaining a pullorum-free flock: 



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 justi- 

 fies the expenditure. 



3. Every reactor, regardless of its value, should be removed from the premises 

 and sold for slaughter immediately upon receipt of the reports. 



4. Off"al from all birds dressed for market or home consumption as well as 

 dead birds that are not fit for consumption should be burned. 



5. The poultry houses, runs, and equipment should be thoroughly cleaned 

 and disinfected immediately after removal of reactors. An empty pen to each house 

 should be provided to facilitate cleaning and disinfection during the winter months. 

 Disinfectants approved by the United States Department of Agriculture should be 

 used. 



