A nonchemical method of controlling the northern fowl mite, Ornithonyssus sulviarum (Canestrini and Fanzago), on caged White Leghorn hens.

Populations of the northern fowl mite on hens but not on roosters were significantly reduced relative to normally feathered chickens when feathers in the vent area were clipped to 2 to 3 mm length. The average difference in egg production between the control (no mites) and the clipped mite-infested hens was only 2.6% during the 22-week study, but the average difference between the control and the unclipped mite-infested hens was 7.6%, which was significantly different (P less than .01). Egg weight, hen body weight, and feed consumption of the three groups of hens were not significantly different.