External parasites (ectoparasites) that target poultry include lice, mites, ticks, fleas and flies. They live on or around the birds, and can disturb them, affect their growth and egg production, and spread disease.
Chickens are infested mainly with biting lice. These irritate the birds, slowing growth and resulting in fewer eggs being laid.
Biting lice spend their entire lives on the chickens, feeding on skin and feathers. They occur mainly on the skin around the vent and on the breast and thighs.
Mites feed on the blood of chickens, and the birds’ growth suffers as a result. Three important types of mites are found on poultry.
- The red mite (Dermanyssus gallinae) is particularly large. It lives in crevices of chicken houses and feeds mainly at night.
- The northern fowl mite (Ornithonyssus sylviarum) is smaller, and lives on the chicken throughout its life. When it is present in large numbers, its droppings and eggs blacken the feathers of the bird.
- The burrowing mite (Knemidocoptes mutans) also lives on the chicken, where it causes itching, loss of feathers and excessive scaliness, leading to thickening and even deformation of the legs.
The soft tick (Argas persicus) feeds on the blood of chickens for short periods and spends the rest of its time in crevices. When they occur in large numbers on chickens, they cause weight loss and a decrease in egg production. They can also cause paralysis and transmit spirochaetosis, a gut condition that leads to diarrhoea.
Many types of fleas infect poultry, the most common type being the sticktight flea (Echidnophaga gallinacea). It feeds on the blood of chickens, and can survive in the cages for a long time.
Flies lay their eggs in the bodies of dead chickens and in chicken droppings.
Cleanliness is crucial in controlling ectoparasites. Inspect the birds daily. Remove droppings at least once a day. Wash and disinfect cages/houses. Remove dead birds without delay.
Various chemicals are available to kill ectoparasites, but it’s important to use the correct kind.
- To control ectoparasites living on and off the chickens, such as in cracks and crevices, treat the birds as well as their environment.
- Before using any chemical, ensure that it’s the correct one for the parasite in question. Read the instructions carefully.
- Flies can be controlled by using sprays, larvicides or fly traps. Sprays (for example, Malasol 1%) or dusts (Carbadust) can control mites, ticks and fleas. When these parasites are present, all chickens should be treated.
Malasol 1% can be used both on the birds and in the cages/houses. Carbadust should be dusted on the birds, not on the cages/houses.
- Chickens should ideally be kept on concrete floors. If the floor is sand, spray it with Malasol 1% to protect the birds from soft ticks.
For more information, contact your nearest animal health technician or vet.
Source: Mashishi, MSK. 2013: ‘External parasites on chickens’ Department of Agriculture, Forestry and Fisheries.