Control of External Parasites in Organic Poultry Production

NOTE: Before applying any pest control product, be sure to read and understand the safety precautions and application restrictions on the label, and make sure that the brand name product is listed on your Organic System Plan and approved by your certifier. For more information see Can I Use this Product for Disease Management on my Organic Farm?

Introduction

There are several external parasites that attack poultry by either sucking blood or feeding on the skin or feathers. The most common ones are lice and mites. An infestation of any external parasite can adversely affect the health and productivity of the flock, including a drop in feed consumption, decreased carcass quality, and lower egg production. Parasites may also be a nuisance to the flock managers: workers often complain of picking up mites when they handle eggs or birds, or of finding chicken lice in their heads. Some people are allergic to these parasites, which can cause severe rashes and/or respiratory problems (Rimac et al., 2010).

Monitoring

It is important to routinely check your flock for external parasites. Monthly examination of the flock and early detection is essential in their control. Most external parasites common to poultry live and feed on the host. Other parasites, such as the red mite, feed on the birds at night but spend the day hiding in building crevices. Therefore, monitoring should include examining the birds at night. Inspect the ventral regions of the birds (spread the feathers to see the base of the feathers and skin), as infestation usually starts in this area. Lice infestations can be detected by observing lice eggs on the base of the feather shafts. Mites usually lay their eggs along the feather shaft.

The scaly leg mite usually affects unfeathered skin, such as the nostrils and shanks. Older hens are the most commonly affected. Such an infestation can cause deformation of the shank, and can cripple the bird and limit its ability to access feed and water.

Prevention

Sanitation and cleanliness are key in the control of parasites. Make sure to clean the walls, floors, roosts, nest boxes, and the birds themselves. Some parasites, such as the Northern Fowl Mite, have been shown to easily transfer from bird to bird. The mites are also able to crawl onto inanimate objects and be spread over a larger distance (Mullins et al., 2001). Some producers spray roosts with a natural oil.

Preventing contact with wild birds and rodents, which can transmit these parasites, is very important. Because of the outdoor requirement, with very possible exposure to both wild birds and rodents, external parasites can be an ongoing challenge in organic poultry production.

Some producers have found it useful to include diatomaceous earth (DE) in dust baths. Diatomaceous earth must be food-grade for use in organic systems—one example is a product called Perma-Guard. Diotomaceous earth kills insects by desiccation, i.e., by drying them out. Additionally, DE has abrasive qualities, and will remove the oily or waxy cuticle layer on the outside of the insect. When this thin, waterproof cuticle layer is gone, the insect dehydrates and dies. Regular use of DE in dust baths has been shown to significantly reduce parasite infestation (Bennett et al., 2011).

Control

For organic producers, there are a few organic pesticides, including PyGanic® Livestock and Poultry Insecticide and Evergreen®, which are pyrethrum-based insecticides derived from chrysanthemums. Eco-Exempt® is a blend of plant oils used to control a broad spectrum of insects.

Some researchers have had success controlling Northern Fowl Mites—which spend their adult life on the bird—by spraying the vent area of birds with a 10% garlic solution in water (Birrenkott et al., 2000). Other vent-applied treatments have been reported to be effective in controlling Northern Fowl Mites (Mullins et al., 2012). High concentrations of a sulfur solution (>5.3%) was shown to eliminate mites for 8–10 weeks. The effect was not as long-lasting with lower concentrations (0.9%). Azadirachtin (derived from the neem tree) at 0.06% reduced, but did not eliminate, mites for 3–4 weeks. Kaolin clay in solution (12% by weight) reduced mites for only one week. These products have no affect on the eggs, so repeated treatments are required.

Sulfur is listed by the Organic Materials Review Institute (OMRI) as "Allowed with Restrictions". While the sulfur itself is allowed, inert carriers will need to be approved before use in an organic system. Kaolin clay and various azadirachtin products are OMRI-listed.

Products with diatomaceous earth are also OMRI-listed and should be applied frequently (every 10–14 days to have efficacy). Refer to http://www.omri.org to review the current status of products.

References and Citations

• Bennett, D. C., A. Yee, Y.-J. Rhee, and K. M. Cheng. 2011. Effect of diatomaceous earth on parasite load, egg production, and egg quality of free-range organic laying hens. Poultry Science 90: 1416–1426. (Available online at: http://dx.doi.org/10.3382/ps.2010-01256) (verified 23 July 2013)
• Birrenkott, G. P., G. E. Brockenfelt, J. A. Greer, and M. D. Owens. 2000. Topical application of garlic reduces Northern Fowl Mite infestations in laying hens. Poultry Science 79: 1575–1577. (Available online at: http://ps.fass.org/content/79/11/1575.short) (verified 23 July 2013)
• Mullins, B. A., D. Soto, C. D. Martin, B. L. Callaham, and A. C. Gerry. 2012. Northern fowl mite (Ornithonyssus sylviarum) control evaluations using liquid formulations of diatomaceous earth, kaolin, sulfur, azadirachtin, and Beauveria bassiana on caged laying hens. Journal of Applied Poultry Research 21: 111–116. (Available online at: http://dx.doi.org/10.3382/japr.2011-00402) (verified 23 July 2013)
• Mullins, B. A., N. C. Hinkle, L. J. Robinson, and C. E. Szijj. 2001. Dispersal of Northern Fowl Mites, Ornithonyssus sylviarum, among hens in an experimental house. Journal of Applied Poultry Research 10: 60–64. (Available online at: http://japr.fass.org/content/10/1/60.short) (verified 23 July 2013)
• Rimac, D., J. Macan, V. M. Varnai, M. Vucemilo, K. Matkovic, L. Prester, T. Orct, I. Trosic, and I. Pavicie. 2010. Exposure to poultry dust and health effects in poultry workers: Impact of mould and mite allergens. International Archives of Occupational and Environmental Health 83: 9–19. (Available online at: http://dx.doi.org/10.1007/s00420-009-0487-5) (verified 23 July 2013)

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