Impact of northern fowl mite on broiler breeder flocks in North Carolina.

The impact of a northern fowl mite (NFM), Ornithonyssus sylviarum (Canestrini and Fanzago), infestation on broiler breeder layers in the field was evaluated by comparing flocks in two adjacent houses (ca. 5,000 birds each). The NFM-free birds produced 3,158.7 dozen more eggs than NFM-infested birds, which was equal to 7.7 eggs per hen housed more than infested birds over the life of the flock. Feed efficiency was affected; feed costs for NFM-infested birds ranged from $ .01 to $ .06/dozen higher than the feed costs for NFM-free birds.