CHAPTER I 
GENERAL METHODS OF CONTROLLING 
DISEASE 
I. Importance of Controlling Disease 
HE ravages of disease add considerably 
to the difficulties of raising poultry in 
all parts of the world. It is the experience 
of poultry rearers that an annual toll has to 
be paid in the lives of young birds and older 
stock. Sooner or later, in addition, an epi- 
demic may break out and result in heavy 
losses and much discouragement. 
It is most important, therefore, to be able 
to recognize the symptoms and to know the 
causes of the many diseases to which vari- 
ous kinds of poultry are subject. Every 
practical effort should be made to reduce 
avoidable mortality. An unexplained 
death should be regarded with concern. It 
may point to the presence of a serious dis- 
ease. When there is not sufficient external 
I 
