used were niaintaiued in a frozen state until time of use. Commercial de- 

 hydration of similar strains of infectious In-onchitis did not materially afTect 

 the response to the vaccination. In the maj(jrity of trials the vaccine was 

 mixed at the farm h}- a representative of the poultr}- department. As the 

 \'(jlume increased in the state, however, it was necessary in manv instances 

 to mix the vaccine beforehand. Such vaccine was picked up at the laboratory 

 by the farmer or field service man. Xo difference in results was noted be- 

 tween those flocks sprayed by a member of the University or those sprayed 

 l)y tlu' ])oultrvman himself. 



Due to the ease of uKjre complete coverage, the majority of flocks 

 spray-vaccinated were done so at night when the chicks were bedded down. 

 Night administration was later observed not to be necessarv providing 

 complete coverage of the chicks could be accomplished. This factor of suc- 

 cessful daytime inoculation depended <in the type of brooding facilities 

 encr)untered. 



On those farms utilizing space heaters, the fans were turned off during 

 administration of the vaccine. The type of brooding equipment used did not 

 aff'ect the results of the vaccination. 



In the case of birds being carried through the growing period to the 

 laying period, it was found necessary, as with commercial vaccines, to re- 

 vaccinate. This revaccination was carried out at night when the birds were 

 bedded down or had gone to roost. Simply spraying the vaccine over the 

 heads of the birds was all that was necessarv to restimulate immunity which 



Drilling and disinfecting the embryos prior to inoculation. 



