Authors :Dr.BhupalBondar (M.V.Sc Poultry Science), Dr. Aditya Kherde (M.V.Sc Poultry Science),Dr.PrajwalChaple (M.V.Sc Pathology), Dr PruthviGulhane (M.V.Sc Poultry Science)
Ectoparasites are external organisms that feed on the outside of poultry, causing significant issues in breeder operations. These pests can increase floor egg numbers because hens avoid nests with parasites and can also lead to skin lesions, infections, and disease transmission. Implementing a robust sanitation program and targeted pesticide use is crucial for preventing and controlling ectoparasites. The shift to larger commercial poultry operations has amplified concerns regarding external parasites. These pests directly threaten the economic value of birds by impeding growth, vitality, plumage, and egg production. Severe infestations can reduce egg production by up to 30% and make birds more susceptible to other parasites and diseases, potentially leading to mortality.
Avian lice
Avian lice are small, wingless insects, typically ranging from 1 to 6 mm in length, with a flattened appearance and elongated abdomen in most cases. They have chewing mouthparts and feed on a variety of materials such as dry skin scales, scab tissue, feather parts, and blood when they puncture the host’s skin or feather quills. While they do not have the ability to fly, they are adept at crawling and can move quickly across the host’s body or between birds in close proximity.
The two most common species of lice affecting poultry are the chicken body louse (Menacanthusstramineus) and the shaft louse (Menapongallinae). The chicken body louse is particularly widespread and can be found in both intensive commercial flocks and smaller backyard flocks. It is around 3 to 3.5 mm long, and its eggs are usually attached to the base of feathers. This species primarily infests areas with sparser feather coverage, such as the vent, breast, and thigh regions, and feeds on feathers and blood by chewing on pin feathers.
On the other hand, the shaft louse (Menapongallinae) infests feather shafts and is less commonly found on chickens compared to the chicken body louse. Other louse species that may infest poultry include the chicken wing louse (Lipeurus caponis), the chicken head louse (Cuculotogaster heterographus), the fluff louse (Goniocotesgallinae), the large chicken louse (Goniodesgigas), the brown chicken louse (Goniodesdissimilis), Menacanthus cornutus, Uchida pallidula, or Oxylipeurus dentatus..
Lice eggs, known as nits, are typically cemented to the base of feathers. They take around 4 to 7 days to hatch and undergo several molts before reaching adulthood, which usually occurs within 10 to 15 days. An adult louse can lay anywhere from 50 to 300 eggs during its approximately 3-week lifespan, contributing to rapid infestation growth if left unchecked.
Lice are usually introduced to a farm through infested equipment (eg, crates or egg flats) or by galliform birds. Lice are best controlled on caged chickens or turkeys by spraying with insecticides. Eggs are not killed, so insecticide treatment should be repeated after 10 days. Birds on the floor are more easily treated by scattering insecticidal dust on the litter or by providing dustboxes containing sand and an insecticidal dust, such as diatomaceous earth or sulfur dust.
Because lice can transfer between bird species in close contact, they can infest other domestic and caged birds, although some species are usually host-specific. Additionally, lice may hitch a ride on louse flies (Hippoboscidae) for transportation to new bird hosts. It’s important to note that certain louse species of geese and swans can act as vectors for filarial nematodes, adding to the complexity of managing lice infestations in poultry operations.
Symptoms
Heavy populations of the chicken body louse decrease reproductive potential in males, egg production in females, and weight gain in growing chickens. Areas of skin irritation 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.
Life cycle of lice
Lice lay eggs on the bird (not under the skin as with mites). The life cycle of a louse takes around 7 days from hatching to a visible louse which can be easily detected on a bird. The lice chomp down to the layer immediately under the main protective skin layer and in those areas of the bird where they are comfortable. A louse found on the back of a head can be a different species to one found under the tail feathers. The process of skin munching and foraging damages the underlying tissues. The result is an inflammatory response can result in dried, crusty fluid loss. Birds become irritated and preen and worry the areas where they are itching. This breaks the feather shafts and results in the typical symptoms – bald birds with rough feathers. These birds are unable to keep warm and production drops are inevitable in colder weather.
Prevention and Control
External parasites are mostly spread by bird to bird contact. Wild birds and rodents may also be responsible for parasites entering the flock. Once detected, it is highly likely that all birds and housing are infected. Prevention and early detection are the best ways to deal with mites and lice. Regularly check birds for signs of mite and lice and check common hiding places such as under perches and in cracks. Once mites and lice are in your flock, they can be difficult to control.
Mites
There are several species of mites that infect poultry. The Northern Fowl mite is usually located around the vent. Therefore, they are often found on eggs and may be detected by staff handling eggs. Scaly leg and depluming mites infest the legs and feet and base of the feathers, respectively.
If environmental conditions are good (temperature and humidity) some mites can live apart from birds for several weeks. Therefore, even with downtime, mites can survive to infect a new flock. Infestations tend to be worse in cool weather and on young birds.
Wild birds are known carriers of mites. Prevent nesting of wild birds on or around poultry houses. Mites can be carried into the house by equipment and egg flats. They live in cracks, crevices, nest boxes and walls (nest boxes and slats offer ideal habitats) during the day and feed at night. Depending on the infesting species, infestations can cause pale combs and wattles, crusty skin on the legs, and birds pulling out their feathers.
Mites are wingless, very small (just visible without magnification) and may look like dark, moving specks. Bird mites (avian mites) are parasitic arthropods in the acari (tick/spider) family. The red mite (Dermanyssusgallinae) and the tropical fowl mite (Ornithonyssus bursa) are two main species that infest chickens, turkeys, pigeons, canaries, and various wild birds worldwide. These bloodsucking mites will also bite people. Chicken mites are nocturnal feeders that hide during the day under manure, on roosts, and in cracks and crevices of the chicken house, where they deposit eggs. Populations develop rapidly during the warmer months and more slowly in cold weather.
The bird mite life cycle consists of egg, larva, nymph, and mature adult. They can complete this cycle in about 7 days, depending on the environment. Heavy infestations of either chicken mites or tropical fowl mites decrease reproductive potential in males, egg production in females, and weight gain in young birds; they can also cause anemia and death
Bed bugs
Bed bug behavior is similar to mites. They live in cracks and crevices during the day and feed at night. Bed bugs can survive for months apart from the birds so downtime will not alleviate a bed bug issue. Inspect cracks, crevices, and eggs for bedbugs which will appear as black spots.
Cimexlectularius (bedbug) is a common bloodsucking parasite of people, but it can also feed on many other warm-blooded animals, including poultry. Bedbugs spend most of their time off the host in cracks and crevices, traveling to the host to feed at night. Because of this life history, it is rare in modern caged-laying operations. Bedbugs require a more complex environment (eg, nestboxes) and may become problematic in furnished-cage or cage-free layer facilities, breeding houses, pigeon lofts, etc.
Adult bedbugs are dorsoventrally flattened, dark brown, and about the size of an apple seed. Nymphs are smaller and lighter brown. Bedbug eggs are laid in cracks and crevices and hatch after 4–12 days. The five nymphal instars all blood feed and last 3–10 days each. The entire cycle (egg to adult) requires 24–128 days depending on temperature (30°C is optimal). Bedbugs can survive for weeks to months without feeding. Infestations cause irritation and blood loss to birds. They have not been found to vector any diseases.
If attacked by large numbers of bedbugs, birds may become irritable and anemic. Bites are usually followed by swelling and itching due to injection of saliva into the wound.
Signs of bedbug infestation on poultry include: bug fecal droppings on eggs and nest boxes, breast and leg skin lesions, egg production will be reduced and increased feed consumption
Control is best accomplished by thoroughly cleaning the houses, reducing hiding places for the bedbugs, using heat treatments, and/or fumigating the houses.
Fleas and ticks
These parasites are occasionally found in breeder operations. Most pesticides that are used to treat other ectoparasites are also effective against fleas and ticks.
The fowl tick, Argaspersicus, is found worldwide in tropical and subtropical countries and is the vector of Borreliaanserina (avian spirochetosis) and the rickettsia Aegyptianellapullorum, which causes fowl disease (aegyptianellosis). In the USA, the Argaspersicus complex has been divided to include Aminiatus, A sanchezi, and A radiatus in addition to A persicus. These ticks are particularly active in poultry houses during warm, dry weather. All stages may be found hiding in cracks and crevices during the day. Larvae can be found on the birds because they remain attached and feed for 2–7 days. Nymphs and adults feed at night for 15–30 minutes. Nymphs feed and molt several times before reaching the adult stage. Adults feed repeatedly, most commonly under the wings, and the females lay as many as 500 eggs after each feeding. Adult females may live >4 years without a blood meal.
Fowl tick infestation can lead to anemia (most important), weight loss, depression, toxemia, and paralysis. Egg production decreases. Red spots can be seen on the skin where the ticks have fed. Because the ticks are nocturnal, the birds may show some uneasiness when roosting. Death is rare, but production may be severely depressed. Fowl ticks are rarely found in commercial cage-layer operations but may be found in cage-free housing, including breeder, pasture, or small-scale flocks.
After houses are cleaned, walls, ceilings, cracks, and crevices should be treated thoroughly with acaricides using a high-pressure sprayer. Cracks and crevices should be filled in.
The sticktight flea, Echidnophagagallinacea, is an occasional poultry pest in temperate areas and a major poultry pest in the subtropical and tropical New World. These fleas may be common in backyard poultry flocks or areas where birds spend a lot of time outdoors or interface with wildlife. Adult fleas are dark brown and laterally flattened. Adult fleas embed in the skin of their host for days or weeks. On chickens, they prefer to attach to the wattles, comb, or face. Without detaching from the host, females lay their eggs, which fall into the litter or soil. Larvae hatch and live on host blood excreted by adult fleas and organic material in the litter or soil. The larvae develop best in sandy, well-drained litter. Larvae pupate and later emerge as adults, which then search for a host. This whole cycle takes about 1–2 months.
Hosts of the adult flea include chickens, turkeys, pigeons, pheasants, quail, people, and many other mammals. Fleas cause irritation, restlessness, and blood loss that results in anemia and death, particularly in young birds.
The most important flea control measures are to remove infested litter and to dust the litter surface with carbaryl, coumaphos, malathion, or pyrethroids to kill immature fleas. Insect growth regulators such as methoprene are also effective. Sticktight fleas can be controlled by topical application of insecticides
CONCLUSION
Controlling ectoparasites in broiler breeder birds involves implementing integrated pest management strategies, including: Regular cleaning and disinfection of poultry houses, Proper waste management to reduce organic debris that can harbor parasites, Use of approved acaricides and insecticides for treating infestations, Monitoring bird health and behavior for early detection of ectoparasite problems, Implementing biosecurity measures to prevent the introduction and spread of parasites.
It’s crucial for poultry producers to work closely with veterinarians and follow recommended protocols for parasite control to maintain the health and productivity of broiler breeder flocks.
