Procedure 



Twenty-five puUorum-disease-free pullets, 17 weeks old, were put into an 

 8 X 12 house with a screened sun porch of the same dimensions. These pullets 

 were purchased as day-old chicks from a flock which has been negative to the tube 

 agglutination test for two years. They were maintained on experiment for a 

 period of eighty-five weeks. 



The feces were obtained from two groups of positive-reacting birds isolated 

 in a 8 X 12 house and were collected from the dropping boards daily. Roosts 

 and dropping boards were screened with wire poultry netting. Feces from Group I 

 of the positive-reacting birds were added to the litter (shavings) daily for 21 

 weeks when a new group of positive-reacting birds was obtained. The addition 

 of feces from Group II was withheld for eight weeks, when daily additions of 

 feces were resumed and continued for 23 weeks. The puUorum-disease-free birds 

 were held for 33 weeks following the termination of the addition of feces to the 

 litter when they were killed and necropsied. 



Approximately one-half to one quart of feces was added to the litter daily. 

 The soiled litter was replaced completely with clean litter four times during the 

 experiment. 



Scratch grain was fed in the litter morning and afternoon. 



The pullorum-disease-free birds were tested by the tube agglutination test 

 (in dilutions of 1:10 and higher) at bi-weekly intervals. The antigen used was a 

 composite of three known agglutinable strains of S. pullorum selected by the 

 Northeastern Laboratory Workers' Conference and was prepared according 

 to the standard methods recommended by this conference. 



Results 



All birds remained negative to the tube agglutination test throughout the 

 experiment. 



The 25 birds (17 birds died during the course of the e.xperiment) were ne- 

 cropsied and S. pullorum was not isolated. 



The following table gives the data showing the length of time individual birds 

 were maintained on experiment. 



The results obtained in this experiment suggest that feces from infected hens 

 are not an important vehicle in the transmission of pullorum disease to older 

 birds kept under an environment approaching natural conditions. 



