216 



were randomized throughout the houses so that each row of cages housed 

 one 24-cage block of each strain. Blocks were divided in half. Hens 

 in one half received a diet with a varying protein level and hens in 

 the other half received a diet with a fixed protein level. 



All hens on the lower rows of cages in house 200 were examined for 

 northern fowl mites. One bird in each cage was marked on the wing with 

 a black water-proof magic marker so both birds could be identified indi- 

 vidually during each mite examination. Mite populations were counted 

 on the day of but prior to the first acaricide treatment and again 36 

 days later (Table 62). Mites on birds in house 100 were not monitored. 



Egg production records were maintained in both houses. Eggs were 

 collected daily and production was calculated on a hen-day basis for 

 both feed protein levels within each block. Because of results from 

 previous trials, Ravap was the acaricide of choice. The test concen- 

 tration of 0.36% was mixed by adding k8 ml of Ravap 28.7% EC to 3-8 1 

 of water. The application rate was 3.84 1 per 60 to 80 birds. Ravap 

 was applied on days 1 and 29 (Table 62) to hens in rows 2 and 3 in 

 both houses (Figure ^3). 



Morning and evening artificial lights supplemented natural light 

 and provided hens with a total of 15 hr of light per day. Water and 



feed were offered ad libitum. 



TM 

 A fly control system, manufactured by Chem-amatic in Bellview, 



Florida, had been installed under the cages in house 200. When an 



automatic timer activated the system, a 0.033% pyrethrin solution was 



dispensed through spray heads located at fixed intervals throughout 



the house. The height of the spray heads was just above the level of 



the walks. 



