Effects of different feather lengths in the vent area of White Leghorn hens on northern fowl mite populations.

Two tests of mature White Leghorn laying hens with feathers in the "vent area" clipped to less than .5, 1.5, or 2.5 cm in length were compared with unclipped hens to determine the differences in northern fowl mite (NFM) populations following artificial infestation. Weekly mite ratings were recorded for: 1) the total hen's body, 2) only the vent area, and 3) the remainder of the hen's body. In both tests, the mean total NFM populations were progressively greater as the clipped length of the feathers increased for 16 weeks postinfestation. Mean NFM populations in only the vent area were significantly less for hens with feathers clipped to less than .5 cm in both tests. There was no significant increase in NFM populations over the rest of the hen's body as a result of feathers clipped in the vent area. Therefore, it would be possible to control NFM at relatively low levels without the use of pesticides if a method for reducing the length of feathers in the vent area of laying hens could be developed.