Diversity and Prevalence of Ectoparasites on Poultry from Open Environment Farms in the Western-United States of Washington, Idaho, Oregon, and California.

Open-environment poultry farms that allow chickens to forage outdoors are becoming increasingly common throughout the United States and Europe; however, there is little information regarding the diversity and prevalence of ectoparasites in these farming systems. Eight to 25 birds were captured and surveyed for ectoparasites on each of 17 farms across the states of Washington, Idaho, Oregon, and California. Among the farms sampled, six louse species (Phthiraptera: Ischnocera & Amblycera) and two parasitic mite species (Acari: Mesostigmata) were collected and identified: Goniodes gigas (Taschenberg, 1879; Phthiraptera: Menoponidae) on one farm, Menacathus cornutus (Schömmer, 1913; Phthiraptera: Menoponidae) on one farm, Menopon gallinae (Linnaeus, 1758; Phthiraptera: Menoponidae) on six farms, Lipeurus caponis (Linnaeus, 1758; Phthiraptera: Philopteridae) on five farms, Menacanthus stramineus (Nitzsch, 1818; Phthiraptera: Menoponidae) on nine farms, Goniocotes gallinae De Geer (Phthiraptera: Philopteridae) on 11 farms, Dermanyssus gallinae (De Geer, 1778; Mesostigmata: Dermanyssidae) on two farms, and Ornithonyssus sylviarum (Canestrini & Fanzago, 1877; Mesostigmata: Macronyssidae) on one farm. The diversity of ectoparasites on these open environment poultry farms highlights a need for additional research on ectoparasite prevalence and intensity in these poultry farming systems.