263 



No attempt to correlate field estimates of mite populations with 

 actual mite numbers present on birds by use of laboratory counting 

 procedures was found in the literature. The results of all northern 

 fowl mite field research performed in the past are based on some type 

 of mite rating system. Hence, the field estimates of northern fowl 

 mite populations on hens (p. 70) were considered to be the better 

 estimate of mite numbers and were the values used for statistical 

 analyses of mite data presented in this dissertation. 



