106 LESSONS !N POULTRY KLLPING — SECOND SLKltS. 



LESSON XI. 



The External Parasites of Poultry. 



IN his liook, " Diseases of Poultry," Dr. Salmon gives a )ist of more llian forty kimis of lice 

 ami mites which Jiilest liomcfctic fowls, — paraeiles which make poultry their special 

 prey. If a poultryman takes pleasure in that kind of knowledge, and has the time at his 

 disposal, there is no reason why he should not study tliese creatures, learn their names, 

 study them microscopically, learn to distinguish between them, and in general become well 

 informed on the sulgect. But practically all that is necessai y is that he should know ho\y to 

 keep them out of his premi;.es, botli by preventing their increase and reducing their numbers 

 when increased to the point where they become troublesome. 



A few lice on -a healthy fowl do no perceptible harm — so long as they are few in numbers. 

 It is even asserted l>y some authorities that a few lice are beneficial rather than injurious, con- 

 suming dead cuticle and causing just enough irritation to prompt the fowl to dust itself — its 

 way of liathing — regularly; this, however, is all theorj , and has not been demonstrated. 

 The evident facl-i are : — 



That fo" U are vet-y rarely wholly free from lice. 



That in limiteil numljers lice ilo little damage. 



That when from any cause tliey become numerous they are a very serious pest. 



Many writers on poultry topics preach constant preventive treatment as the only sure way of 

 avoiding losses through tlie ravages of lice. It is a very common thing to see statements pro- 

 claiming lice as a constant menace to the health and profitableness of fowls, and urging the 

 necessity of unceasing warfare against them. 



Impressed by such statements many poultry keepers carry on a systematic treatment for lice 

 which takes a great deal of time and labor, adding greatly to the drudgery of their routine 

 work. 



Such continuous preventive treatment is not necessary when fowls are kept under ordinary 

 good conditions, u itli no conditions existing which are favoral)le to the increase of lice. 



When I make this statement I do not wish any reader to misunderstand it. It will not do to 

 ;i-~ume that conditions are right, and therefore — in accordance with my statement — precau- 

 tions against lice and treatment for lice are not needed. 



Look at the matter from the other side. Kind out — if you do not already know — to what 

 extent lice affect your poultry, or would affect them under your management with special pre- 

 cautions against lice omitted, and then, if lice are troublesome try to find in what respect con- 

 ditions supposed to be good, are favorable to the Increase of vermin, and therefore bad. 



The most frequent conditions favorable to the Increase of lice, are debilitated stock, dark 

 111 ventilated houses, and buildings that liy reason of the abundaace of conveniences in the 

 fittings are difficult to keep clean, and furnish many nooks and corners to which the sunlight 

 rarely penetrates. 



