CHAPTER III 

 The Diagnosis of the Diseases of Poultry 



The first thing that the poultry keeper whose birds are ill 

 wants to know is : " Uliat ails my chickens? " Before he can 

 use this or any other book on poultry diseases effectively in 

 getting advice for the treatment of disease he must diagnose 

 the trouble. It is the purpose of this chapter to help him do 

 this, and in this way make this book more useful to the 

 practical poultryman. At the outstart it should be said 

 that the absolutely certain differential diagnosis of particular 

 diseases of yoidtry, by the farmer or youUryman, either on the 

 basis of external symptoms or post-mortem examination, is in 

 nearly every case impossible. The best that can be done prac- 

 tically is to determine into what general class of diseases a 

 particular trouble falls. 



There are two general sources of information upon which to 

 base a diagnosis of disease. These are : 

 I. External symptoms. 



II. Post-mortem examination. 



EXTERNAL SYMPTOMS, WITH A TABLE TO AID IN THE IDENTIFI- 

 CATION OF THE CHIEF CLASSES OF POULTRY DISEASES 



There are certain external symptoms which are charac- 

 teristic in a way of nearly all diseases. These symptoms 

 merely indicate that the bird is sick; they are of no value for 

 purposes of differential diagnosis. 



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