225 



200. The mite populations in the control group in the west end of the 

 house were significantly lower than those of the treated group. This 

 is reflected in the differences in the mean rankings by strain between 

 the east and west ends of the house (Tables 67 and 68). The northwest 

 section, where the pyrethrin spray system was partially operating, was 

 where the control birds were located. Tables 69 and 70 show the post- 

 treatment mite counts by treatment and strain for the west and east 

 ends respectively of house 200. Since the mite means for the control 

 groups in both ends of the house were almost numerically equal it was 

 discounted that the pyrethrin spray system had any effect on the mite 

 popu lat ions. 



Egg production means by treatment and strain for house 100, house 

 200, and houses 100 and 200 combined, are shown in Tables 71, 72, and 

 73 respectively. There were no significant differences in egg produc- 

 tion due to treatment when strain differences were ignored. Mean 

 rankings by strain were very similar in all three tables. 



Table Ik gives the egg production means by week, with and without, 

 treatment being taken into consideration. Weeks 6 and 7 'were signifi- 

 cantly different from each other and from weeks 1 through 5, but there 

 were never any significant differences between treatments at any point. 

 There were no differences in egg production due to feed protein level 

 and results are not reported. 



A plot of weekly egg production means by treatment is shown in 

 Figure kk. A nonsignificant drop (ca. \%) in egg production occurred 

 3 days after both applications of Ravap (Table ]h, Figure hh) , possibly 

 due to treatment stress. In each case, birds recovered and within 7 

 davs began to lay at a numerically higher rate than the control birds. 



