average number of tested birds per flock was 1.815 which is much less than the 

 average in the previous season. 



In the group tested for three or more consecutive years, there were 249 flocks, 

 representing 1,041,523 tests of which 0.08 percent were positive. Three flocks 

 were classified as infected. One flock had revealed infection the previous two 

 years. In the other two flocks the infection constituted a "break" of unknown 

 origin. One of these flocks had to be sold because of the economic hardship caused 

 by the infection. The average number of birds per flock in this group was 3,927. 



For all the four groups, 311 flocks were tested, representing 1,101,543 birds 

 and 1,169,822 samples, of which 0.13 were positive. The 288 flocks that were 100 

 percent tested and nonreacting contained 1,059,257 birds or 96.16 percent of the 

 total birds tested. Five flocks were classified as positive. The percentage of reactors 

 among these birds was 8.36. 



During the past year, 63 or 18.64 percent of the flocks tested in 1953-54 were 

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

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

 should procure replacement stock from officially recognized pullorum-passed and 

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

 tion of infection. 



APPEARANCE OF INFECTION IN FLOCKS PREVIOUSLY NEGATIVE 



During the past year pullorum "breaks" were observed in five flocks, a slight 

 increase over the previous season. Three of the flocks had more than 0.5 percent 

 reactors on the first test. In two flocks the stock was received from the same hatch- 

 ery, and it is possible that a common source of infection was responsible for these 

 two "breaks." In two flocks inadequate preventive measures were considered as 

 the explanation for the "breaks." In the fifth flock, infection had been detected 

 the previous year, but the flock had fulfilled the requirements to meet the pullorum- 

 clean grade, but apparently the infection had not been eliminated completely from 

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

 flocks during the past 15 years. 



Flock owners should be reminded that precautions frequently violated are (1) 

 the purchase of questionable stock, (2) hatching from pullets before they are tested, 

 (3) hatching of chicks or poults at a hatchery of unknown pullorum status. 



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 puUorum-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. 



