298 



POULTRY PRODUCTION 



The most frequent cause for spraying is the appearance of 

 the chicken mite. It is usually first noticed on the under 

 side of the perches or in the corners of the nests. This tiny, 

 spider-Ijke bloodsucker does not live on the body of the hen as 

 does the less troublesome louse, but at some place where it can 

 make its way onto the fowl's body for the purpose of feed- 

 ing with fair regularity. Unless promptly checked, they 

 multiply with enormous rapidity, particularly in warm 

 weather, and quickly sap the vitality of the stock and 

 often cause death. In order to eradicate them it is always 

 necessary to spray twice and often three times. 



Fig. 169 



An excellent type of permanent poultry-house. Note the box for saving 

 the droppings at the right end of the building. (Courtesy of Purdue Experi- 

 ment Station.) 



Most of the commercial coal-tar dips kill the mites, but 

 it is difficult to make them penetrate far enough into Uie 

 cracks between the boards to reach and destroy the eggs. 

 The result is that a new generation soon appears. It is 

 necessary to spray again in order to destroy these. The 

 period between sprayings is governed by the prevailing 

 temperature. If it is very warm the second spraying should 

 follow the first in five to seven days. If it is rather cool, 

 ten days will be about right. 



Value and Preservation of Poultry Manure. — ^With reference 

 to conserving the value of the fertility in the droppings, 



