26 MASS. EXPERIMENT STATION BULLETIN 407 



67. Is it necessary to clean and disinfect premises after reactors are re- 

 moved? Thorough cleaning and disinfection of the houses following the removal 

 of the reactors is a very important and necessary step in an effective eradication 

 program. Thorough cleaning of all parts of the pen and its equipment is essential 

 to eliminate and destroy the causative organism of pullorum disease. A reliable 

 disinfectant should be applied generously after the thorough cleaning. In extreme 

 low temperatures a liquid disinfectant may be employed if a vacant pen is main- 

 tained on the plant. It is unlikely that thorough cleaning and disinfection can 

 be accomplished in a pen while it is occupied. The dirty litter should be disposed 

 of in such a way that it will not serve as a source of infection to birds. The 

 sanitary aspect of a poultry plant should not be neglected, as is too often the case. 



68. What disinfectant should be used? Any of the "permitted" disinfectants 

 approved by the United States Department of Agriculture are applicable for 

 general disinfection of poultry houses and equipment. Poultrymen have access 

 to the list of "permitted" disinfectants through their local county agents. 



69. Should owners of pullorum disease-free flocks practice custom hatching? 



Pullorum infection is readily introduced into flocks or hatcheries through the 

 practice of custom hatching if the eggs come from flocks which are untested, 

 improperly tested, or known to be infected. Unless the owner is certain that his 

 customers are supph'ing noninfective eggs, custom hatching is a disease hazard 

 to his flock. Flock owners and hatcherymen too often fail to check the pullorum 

 status of flocks from which eggs are selected for hatching. 



70. Should owners of infected or untested flocks practice custom hatching? 



Investigators have shown that infection may spread in the incubator; therefore, 

 in order to prevent the dissemination of the disease, the practice of selecting 

 hatching eggs from an infected or untested flock must be condemned. The first 

 consideration for such owners should be to establish a pullorum disease-free flock, 

 which will be for the good of the industry as well as for their benefit. 



71. What dangers are associated with the practice of having eggs hatched 

 away from the premises? The owner who follows this practice subjects his flock 

 to the same hazards as the owner who does custom hatching. In fact it may be 

 a more dangerous practice because he has no control over customers supplying 

 eggs to the same hatchery. A thorough- investigation of the pullorum disease 

 standing of the flocks and the business integrity of the customers should be made 

 to assure the maximum elimination of hazards. However, even with the utmost 

 care, one may introduce infection through this practice. 



72. Does custom hatching facilitate the establishment and maintenance of 

 pullorum-free flocks? Yes and No. If hatcherymen select eggs only from flocks 

 officially recognized as pullorum-free, custom hatching should aid in the establish- 

 ment and maintenance of pullorum-free flocks. However, if hatching eggs are 

 selected from flocks of questionable status or known to be infected, no progress 

 in the eradication of the disease is to be expected. 



73. Is it safe to buy chicks from a hatchery that selects hatching eggs from 

 both infected and non-infected flocks? No. Hatcherymen that select their 

 hatching eggs from untested flocks, known infected flocks, and pullorum-free 

 flocks can not produce chicks that can be considered free of pullorum infection. 

 Regardless of how carefully the hatchery may be operated, as long as eggs from 

 infected stock are selected for hatching there is danger that the disease may spread 



