Lice and Chickens

There are many species of lice that affect various species of poultry and waterfowl, some are more common than others. Avian lice, which belong to the order Mallophaga, have a life cycle of ~3 weeks and normally feed on bits of skin or feather products. Lice may live for several months on the host but only remain alive for ~1 week off the host. People and other mammals may harbor avian lice, but only temporarily.

Treatment

The only approved products for poultry are Elector PSP and permethrin dusts/sprays that are specifically labeled for poultry. Both products must be applied as directed on the label – any deviation from the label nullifies the ZERO egg withdrawal.

Ivermectin (injectable form only) is another option, but is used off-labeled and has an 8 week egg withdrawal.

• Applied topically, 3-4 drops for standard size breeds, 1-2 drops for bantam breeds
• Orally 0.2mg/kg
• Injected sub cutaneous 0.2mg/kg

Coops must be cleaned thoroughly – strip out all bedding, get all wood surfaces as clean as possible. Spray coop with permethrin or Elector, making sure to get all nooks and crannies.

Treatment may need to be repeated in 7-14 depending on the infestation and the life cycle of the specific louse being treated.

Prevention

Keep coop clean and dry and provide proper dust bath areas for your flock. Dust baths need to remain dry. Construction sand, peat moss, garden sulfur and wood ash are all things that can be added to a dust bath. Monitor birds to ensure they are dust bathing on a regular basis – larger birds may not dust bathe as they should. Check birds over more often if you have a high wild bird population as they can be a source for mites.

Chicken Body Louse

Menacanthus stramineus, is the most common species on domestic birds, and probably the most damaging one. It is rather large (2.5 to 3.5 mm long) and of a brownish color. It feeds mainly on feather debris, but is capable of sucking blood. It lives mostly on the skin of birds, seldom on the feathers, and prefers body parts with few feathers, e.g. around the vent, although in case of heavy infestations it may be found also on the head, under the wings and on the chest. The eggs are laid in clusters on the feathers or directly on the skin.

Shaft Louse (less common)

Menopon gallinae, feeds mainly on skin and feather debris, but may also suck blood from the wounds it produces. It prefers the chest, the shoulders and the back of birds. Eggs are whitish and are laid often in clusters at the base of the feathers.

Wing Louse or Depluming Louse

Lipeurus caponis is 2.0 to 2.5 mm long, and has a grayish color. It is found mainly in the inner part of wing, tail and head feathers. It feeds intensively on parts of the feathers.

Head Louse

Cuclotogaster heterographus is about 2.5 mm long and is found mainly on the head and the neck of birds. It prefers to stay close to the skin or at the base of the feathers. It does not suck blood, but feeds on skin and feather debris. It is more frequent on young birds and turkeys. Heavy infested birds may even die before maturity.

Fluff Louse

Goniocotes gallinae is one of the smallest lice of poultry, only 0.8 to 1.5 mm long. It is found all over the birds’ body, but less densely on the head and the wings, on the fluff or base of the feathers. It also feeds mainly on feather debris.

Large Chicken Louse and Brown Chicken Louse

Goniodes gigas and Goniodes dissimilis are about 3mm in length and are brown in color. Eggs are laid on the feathers. A small infestation generally poses no issue for the bird. Goniodes dissimilis is more abundant in temperate climates while Goniodes gigas is more abundant in tropical climates.

Slender Pigeon Louse

Columbicola columbae is 2.0 t o2.8 mm long. It can be found all over the body, especially at the inner side of the wing feathers. IT feeds on feather debris. Eggs are laid on the small feathers under the wings.

Body Louse

Menacanthus cornutus is a fairly large louse that can occur in large numbers in backyard flocks.

Small Body Louse

Uchida pallidula and Oxylipeurus dentatus

Large Turkey Louse

Chelopistes meleagridis

Slender Turkey Louse

Oxylipeurus polytrapezius

Because lice transfer from one bird species to another when the hosts are in close contact, other domestic and caged birds may be infested with species of Mallophaga that are usually host-specific. Lice also sometimes reach new bird hosts by using louse flies (Hippoboscidae) for transportation. Some lice of geese and swans are vectors of filarial nematodes.

Heavy populations of the chicken body louse decrease reproductive potential in males, egg production in females, and weight gain in growing chickens. The skin irritations are also sites for secondary bacterial infections. Other species of lice are not highly pathogenic to mature birds but may be fatal to chicks. Examination of birds, particularly around the vent and under the wings, reveals eggs or moving lice on the skin or feathers.

Lice are usually introduced to a farm through infested equipment (eg, crates or egg flats) or by galliform birds. Eggs are not killed, so insecticide treatment should be repeated after 10 days.

Resources

https://www.merckvetmanual.com/…/ectopa…/lice-of-poultry

Parasitipedia

Veterinary Entomology: Arthropod Ectoparasites of Veterinary Importance

Medical and Veterinary Entomology

#CVCLice