The Poultry Red Mite, Dermanyssus gallinae, travels far but not frequently, and takes up permanent residence on farms.

Management of Dermanyssus gallinae, a cosmopolitan hematophagous mite responsible for damage in layer poultry farming, is hampered by a lack of knowledge of its spatio-temporal population dynamics. Previous studies have shown that the circulation of this pest between farms is of strictly anthropogenic origin, that a mitochondrial haplogroup has been expanding on European farms since the beginning of the 21st century and that its local population growth may be particularly rapid. To refine our understanding of how D. gallinae spreads within and among farms, we characterized the genetic structure of mite populations at different spatial scales and sought to identify the main factors interrupting gene flow between poultry houses and between mitochondrial haplogroups. To this end, we selected and validated the first set of nuclear microsatellite markers for D. gallinae and sequenced a region of the CO1-encoding mitochondrial gene in a subsample of microsatellite-genotyped mites. We also tested certain conditions required for effective contamination of a poultry house through field experimentation, and conducted a survey of practices during poultry transfers. Our results confirm the role of poultry transport in the dissemination of mite populations, but the frequency of effective contamination after the introduction of contaminated material into poultry houses seems lower than expected. The high persistence of mites on farms, even during periods when poultry houses are empty and cleaned, and the very large number of nodes in the logistic network (large number of companies supplying pullets or transporting animals) undoubtedly explain the very high prevalence on farms. Substantial genetic diversity was measured in farm populations, probably as a result of the mite's known haplodiploid mode of sexual reproduction, coupled with the dense logistic network. The possibility of the occasional occurrence of asexual reproduction in this sexually reproducing mite was also revealed in our analyses, which could explain the extreme aggressiveness of its demographic dynamics under certain conditions.

Measuring behaviour in hens using an ethogram to assess analgesia during further refinement of a high welfare, on-hen, poultry red mite feeding device.

Background: To refine an on-hen mite feeding device, an ethogram was employed to measure the reactions of hens during a routine experimental procedure (feather plucking) and to assess effects of analgesic cream on those reactions. Methods: Three experimental groups were used; one treated with EMLA 5% before plucking ("EMLA group"); one with aqueous cream ("placebo group") and a "no treatment" group. Behaviours were measured and compared on three days: 'dummy handling day' i.e. no plucking; 'plucking day', plucking the left thigh; and 'treatment day' i.e with right thighs plucked post-treatment. Poultry red mite feeding assays were performed to examine effect of creams on mite feeding rates, mortality and fecundity. All data were analysed using generalised linear (mixed) modelling approaches. Results: Use of the ethogram demonstrated no significant difference in hen behaviours in the EMLA group between dummy handling day and treatment day (p = 0.949) alongside a significant reduction in measured behaviours between plucking day and treatment day in the same group (p = 0.028). There was a statistically significant increase in measured behaviours from the dummy handling day to the plucking day in both placebo (p = 0.011) and no treatment group (p < 0.001). Effect sizes and directions were similar between dummy handling and treatment days in the 'placebo' and 'no treatment' groups, though not statistically significant (placebo, p = 0.064; no treatment p = 0.069). Mite feeding in the EMLA group was significantly lower than in the no treatment group in feeding assay 1 (p = 0.029) only. Mite mortality and fertility were unaffected. Conclusions: The ethogram successfully measured changes in observed behaviours between the dummy handling session and procedures. No adverse effects of EMLA cream on hens were demonstrated at 3mg/kg in hens. Use of analgesia for this routine procedure improves hens' experiences during experimental trials.