FOURTEENTH ANNUAL YEAR BOOK— PART X. 721 



.he straw is stacked in a feed yard for a few months and then applied 

 as a fertilizer. This plan affords the work horses of the farm some feed 

 during the winter and permits the straw to decay to some extent, putting 

 it in better condition to handle. 



5. It should be noted that neither crop residues nor any other fertiliz- 

 ing material are to be applied to plots 1, 5 and 10. All crops are to be 

 removed from these plots and nothing returned. 



6. Potassium may be applied in potassium chloride, potassium sulphate 

 or kainit. The chloride and sulphate should be used at the rate of 200 

 to 300 pounds per acre, and the kainit at the rate of 1,000 pounds per 

 acre, once in a four year rotation. 



IMPORTANT POULTRY DISEASES. 



BY D. E. SALilOX, D. V. il. 



(Farmers' Bulletin 530, U. S. Department of Agriculture.) 



IXTKODUCTIOX. 



Fowls are liable to be affected by a considerable number of diseases, 

 some of which spread rapidly through the flock and kill a large part of 

 the birds. They may also be infested by various kinds of parasites, 

 some of which live on the surface of the body and others in the crop, 

 stomach, or intestines. These parasites are injurious because they take 

 a part of the nourishment which should be used by the bird to put on 

 flesh or to produce eggs, and also because by their movements and their 

 biting they cause irritation and inflammation of the parts which they 

 attack. 



The contagious diseases, which are caused by animal and vegetable 

 germs, and the weakness and loss of flesh caused by the larger parasites 

 to which reference has just been made, are the most important condi- 

 tions which the poultryman has to consider in the endeavor to keep his 

 birds in a healthy condition. These germs and parasites should be kept 

 out of the flock by suitable preventive measures, because disease may be 

 avoided in this way much more easily and cheaply than it can be cured. 

 The aim in studying the diseases of birds is, therefore, to learn how to 

 prevent such diseases rather than how to cure them. 



There are some cases in which medicines may be advantageously given 

 or applied to fowls, but as a rule when a bird becomes sick it is better 

 to kill it, because the cost of the medicine and the value of the time re- 

 quired to carry out the treatment are greater than the value of the 

 birds which are cured. Another reason for killing sick birds is that 

 they may be affected by a contagious disease which before it is recog- 

 nized may spread to many other birds in the flock. A third reason for 

 killing is the fact that a bird being sick indicates that it is more sus- 

 ceptible to disease than the other birds of the flock, and in order to 

 establish a flock which is able to resist disease such susceptible birds 

 must be weeded out, 

 46 



