External Parasites 211 



necessary to give some individual treatment to brooding 

 hens and young chicks. It is also necessary to treat sick 

 hens which are not able to use the dust bath. While it is 

 theoretically possible to exterminate the pests and keep the 

 flock free from them by avoiding the introduction of infected 

 birds, this ideal condition prevails in very few poultry plants. 

 In almost all flocks there are enough lice present to cause 

 trouble if conditions favor their development. 



How to Make an Effective and Very Cheap Lice Powder. — 

 When the treatment of individual birds for lice becomes 

 necessary some kind of powder dusted into the feathers 

 thoroughly has been one of the most effective and advisable 

 remedies. The powder used must be of such nature, however, 

 that it will be effective. There are so-called "lice powders" 

 on the market which are no more effective than an equal 

 quantity of any inert powdered substance would be. It is 

 not only a waste of money but of time as well to use such 

 powders. At the Maine Station no lice powder has been 

 found that is so satisfactory as that originally invented by 

 Mr. R. C. Lawry, formerly of the poultry department of 

 Cornell University. The following matter regarding this 

 powder (which can be made at a very low cost) is quoted 

 from a circular issued by the Maine Station : 



"In using any kind of lice powder on poultry, whether 

 the one described in this circular or some other, it should 

 always be remembered that a single application of powder 

 is not sufficient. When there are lice present on a bird 

 there are always unhatched eggs of lice (' nits ') present too. 

 The proper procedure is to follow up a first application of 

 powder with a second at an interval of 4 days to a week. If 

 the birds are badly infested at the beginning it may be neces- 

 sary to make still a third application. 



" The lice powder which the Station uses is made at 

 a cost of only a few cents a pound in the following way : 



