Common poultry parasites of backyard hens
As the incidence of backyard hens being presented in practice increases, it is important that veterinary nurses can identify the commonly found poultry pests and know how best to advise owners on treatment and prevention. Untreated parasites (both external and internal) can result in debilitation and in some cases can cause death.
While the current lack of treatment options available to vets for use in backyard poultry remains so limited, there are a number of ways in which poultry can receive support. The author puts forward treatment options currently licensed for use in chickens.
General symptoms of external parasite infestation include:
Some common parasites found on chickens are listed below. Routine checking of feathers, especially around the vent area, will help to quickly identify parasitic problems. Prevention of wild birds near chicken accommodation will help to limit external parasites; new stock should always be quarantined.
The chicken body louse Menacanthus stramineus is usually 1–3 mm in length, yellow in colour, and flat in appearance. It has a life cycle of around 3 weeks, laying eggs which pass through three nymph stages before becoming adult. This louse is commonly found around the vent area and under the wings. Lice may live for several months on the host but only remain alive for roughly a week off the host (Phillips, 2013). Chickens are less commonly infested with Menopon gallinae (on feather shafts), Lipeurus caponis (mainly on the wing feathers), Cuclotogaster heterographus (mainly on the head and neck), Goniocotes gallinae (very small, in the fluff), Goniodes gigas (the large chicken louse), Goniodes dissimilis (the brown chicken louse), Menacanthus cornutus (the body louse), Uchida pallidula (the small body louse), or Oxylipeurus dentatus (wing louse). Louse eggs are white and are laid at the feather root. Physical removal of the eggs is difficult without actually removing feathers (Figure 1). Lice feed by biting through the skin and ingesting serum ooze and skin debris. Infestation is more likely during autumn and winter months. Direct bird to bird contact is the usual method of transfer. People and other mammals may harbour avian lice, but only temporarily (Phillips, 2013). Although lice are not life-threatening, infestations can lead to loss of condition, discomfort and skin irritation.