In the two-year group the reactors were identified in one flock. The infection 

 in this flock was eliminated through retesting. The number of birds tested in this 

 group was considerably greater than in the previous season. The average number 

 of birds to a flock was 2,985. 



In the group tested for three or more consecutive years, there were 229 flocks, 

 representing 992,356 tests, of which 0.05 percent were positive. Only one flock 

 was classified as positive at the end of the testing year. Two other flocks were 

 infected but the infection was eliminated through retesting before the termination 

 of the season. The average number of birds to a flock in this group was 4,101. 



For all four groups, 285 flocks were tested, representing 1,077,449 birds and 

 1,144,365 samples, of which 0.08 percent were positive. The 275 flocks that were 

 100 percent tested and nonreacting contained 1,060,746 birds or 98.45 percent of 

 the total birds tested. Two flocks were classified as positive. The percentage of 

 reactors among these birds was 8.88. 



During the past year, 57 or 18.33 percent of the flocks tested in 1954-55 were 

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

 of flocks. If flock owners find it necessarv to omit testing for a year or more, they 

 should procure replacement stock from officially recognized pullorum-passed and 

 pullorum-clcan flocks. Adequate precautions should be taken against the introduc- 

 tion of infection. 



APPEARANCE OF INFECTION IN FLOCKS PREVIOUSLY NEGATIVE 



This is the first year in the history of testing that no "breaks" were observed 

 in flocks that were negative the previous season. This is most encouraging, and 

 it is hoped that this record may continue. In table 3 is given the incidence of 

 "breaks" among Massachusetts tested flocks during the past 15 years. 



Flock owners and hatcherymen should constantly observe strictest vigilance 

 against the introduction and spread of the disease. 



The following measures have been found to be eff'ective 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 justifies 

 the expenditure. 



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

 and sold for slaughter immediately upon receipt of the report. 



4. Offal from all birds dressed for market or for 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. 



6. Birds removed from the premises to egg-laying contests, exhibitions, etc., 

 should be held in quarantine and determined free of disease before they are read- 

 mitted into the flock. 



