Thanks, Kate.
I also just found this study which looks promising, but I have no idea how much neem oil to use on the hen:
Azadirachtin-impregnated traps for the control of Dermanyssus gallinae
Jenny Lundha, b, d, Daniel Wikteliusa, c and Jan Chirico
Abstract
The effect of neem oil (azadirachtin), originating from the tree Azadirachta indica, was investigated as a potential compound to control the poultry red mite, Dermanyssus gallinae. In vitro tests were performed to determine the most appropriate formulation of neem extracts and concentration of the substance to be used. Cardboard traps containing 20% neem oil were placed at the mites aggregation sites, out of reach of the hens, in a floor system for layers containing approximately 2400 birds. Treated traps were replaced every week for 4 weeks. Throughout the study, the parasite population was monitored by collections of mites with untreated plastic traps. A 92% reduction of D. gallinae was recorded.
Keywords: Dermanyssus gallinae; Control methods-arthropoda; Traps; Azadirachtin
Article Outline
1. Introduction
2. Materials and methods
2.1. In vitro test I, acaricidal effect of neem on D. gallinae (Ivt1)
2.2. In vitro test 2, determination of neem concentration (Ivt2)
2.3. Experimental sites and animals
2.4. Impregnated traps and monitoring traps
2.5. Statistical methods
3. Results
3.1. Acaricidal effects of neem on D. gallinae (Ivt1)
3.2. Determination of neem concentration (Ivt2)
3.3. Reduction of mites under field conditions
4. Discussion
Acknowledgements
References
http://www.sciencedirect.com/scienc...serid=10&md5=8c0c5159f439c7ba681d61108e7fc8e7