CHAPTER III. 



The; Diagnosis of the; Diseases of Poultry. 



The first thing that the poultry keeper whose birds are ill 

 wants to know is : "What 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 abso- 

 lutely certain differential diagnosis of particular diseases of 

 poultry, by the farmer or poultryman, either on the basis of 

 external symptoms or post-mortem examination is in nearly 

 every case impossible. The best that can be done practically 

 is to determine into zvhat general class of diseases a particidar 

 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, W^TH A TABLE TO AID IN THE IDENTIFI- 

 CATION OF THE CHIEF CLASSES OF POULTRY DISEASES. 



There are certain external symptoms which are characteristic 

 in a way of nearly all diseases. These symptoms merely indi- 

 cate that the bird is sick; they are of no value for purposes of 

 differential diagnosis. 



These general symptoms of illness may be described as fol- 

 lows : A sick fowl is usually quiet, and does not move about 

 unless disturbed. It stands or sits with the neck contracted so 

 that the head is pulled well in to the body, giving the bird a 

 "humped up" appearance. The eyes are often closed, entirely 

 or partly, giving the bird a sleepy appearance. Often the 

 feathers are roughened and stick out all over the body. The 

 comb and wattles may be dark or, on the other hand, may be 

 very pale. 



