POUIvTRY DISEASES AND THEIR TREATMENT. I25 



either case but treatment must be repeated 2 or 3 times at inter- 

 vals of a few days to destroy those that hatch after the treat- 

 ment or are concealed beyond its reach. A routine procedure 

 by which a poultry plant can be kept free from parasites is very 

 useful. The following method has proven very successful at 

 the Maine Experiment Station and is described in Circular 352 

 of that Station : 



"The routine method which the Station uses in handling its 

 stock with reference to the lice problem is as follows : 



"All hatching and rearing of chickens is done in incubators 

 and brooders. The ■ growing chickens are never allowed to 

 come into any contact whatever with old hens. Therefore, 

 when the pullets are ready to go into the laying houses in the 

 fall they are free from lice. Sometime in the later summer, 

 usually in August or early in September, the laying houses are 

 given a thorough cleaning. They are first scraped, scoured 

 and washed out with water thrown on the walls and floor with 

 as much pressure as possible from a hose. They are then given 

 two thorough sprayings, with an interval of several days inter- 

 vening, with a solution of cresol such as is described in Chap. 

 II. Then the roosting boards, nests, floors and walls to a 

 height of about 5 feet are thoroughly sprayed with the lice paint 

 (kerosene oil and crude carbolic acid described .on p. 135). 

 Finally, any 3^earling, or older birds, whether male or female, 

 which are to be kept over for the next year's work are given 

 2 or 3 successive dustings, at intervals of several days to a 

 week between each application, with the lice powder described 

 on p. 130, before they are put into the cleaned houses. 



"As a result of these methods the Station's poultry plant is 

 at all times of the year practically free of lice." 



This method keeps the flock free from lice and the mites 

 which live upon the surface of the skin, but would not destroy 

 those mites which penetrate the skin and cause scabies. These 

 and other more rare parasites should be destroyed when present 

 by special methods. The description of, and treatment for each 

 class of external parasite is given below. 



A. EicE (maelophaga). 



Lice are probably the most widely distributed parasite of 

 poultry. They are so common that flocks of fowls that have 

 not been treated to remove lice for a long time are almost sure 



