Occurrence: Worldwide. Particularly serious in warmer temperate areas and in older houses with roosts.   Species affected: Chickens, turkeys, pigeons and some wild birds.   Age affected: All.

Causes: A mite of the order Acarina- Dermanyssus gallinae, also know as red mite, roost mite and poultry mite.

Effects: Increase in feed consumption accompanied by lower production. Serious infestations are associated with anaemia, and can cause death, particularly in chicks and settling or laying hens. Birds may refuse to lay in infested nests. Often resistant to treatments, so difficult to control.

The chicken mite (Dermanyssus gallinae), also called red mite, roost mite, or poultry mite, is found worldwide. It is particularly serious in warmer parts of the temperate zone in older poultry house with roosts. The mite is rare in modern large commercial caged-layer operations but is seen frequently in modern broiler breeder farms. It can be identified by the shape of the dorsal plate and by the long whip-like chelicerae that appear to be stylets.

The adult female measures about 0.7mm x 0.4mm, varying in colour from grey to deep red, depending on its blood content. The life cycle may be completed in as few as 7 days. Adult females lay eggs in surroundings of the hosts 12-24 hours after their first blood meal. Eggs hatch in 48-72 hours when warm. The 6-legged larvae moult in 24-48 hours without feeding, becoming first-stage bloodsucking nymphs; they then moult to second-stage nymphs in another 24-48 hours and soon afterwards moult to the adult stage.

Chicken mites can live up to 34 weeks without food.

Chickens are the most common hosts, but these mites may occur on turkeys, pigeons, canaries and several species of wild birds. People may also be attacked, and invasions of human dwellings (apartments, hospitals, doctors’ offices) by mites from outdoor pigeon nests are frequently seen. English sparrows may transmit this parasite because of the habit of lining their nests with chicken feathers. These mites may not only produce anaemia, thereby seriously lowering production and increasing feed consumption, but actually kill birds, particularly chicks and settling or laying hens. Birds in production may refuse to lay in infested nests.

An increase in feed consumption accompanied by lower production is a sign that poultry houses should be examined for mites. These mites often can be found by looking under loose clods of manure, under slats in a breeder house, in nests or in cracks and crevices of posts and roof bracing. They are evident as tiny red to blackish dots, often clustered together. Inspection during the night is usually necessary to find mites on birds.

Occasionally these mites may be found on the shanks of both hens and rooster, but care must be taken to differentiate them from northern fowl mites that also appear on the legs.

Lice, are members of the Class Insecta, characterised by a body divided into three regions (head, thorax, abdomen), chewing-type mandibles located ventrally on the head incomplete metamorphosis, no wings, dorsoventrally flattened body, and short antennae with 3-5 segments.

It is necessary to examine bedding, roosts, walls, cracks and crevices and beneath manure clods. Nest material, dust and other material collected in the house can be spread out on a white pan and examined. The arthropods can be seen crawling on the pan. Night-time examination of birds may detect parasites that feed on them at night. Poultry infested with parasites exhibit irritation and react by scratching and preening. Any unexplained production drop or increase in feed conversion is cause to look for external parasites.

Mites are more easily seen with a magnifying lens.

Galliform wild or domestic birds should never be allowed to come into contact with poultry flocks.

To monitor birds in a production facility, 20-50 birds should be checked a minimum of two times a month.

• Birds should b checked at random and should be chosen from all parts of the house.
• The vent, head and legs should be closely examined.
• If parasites are found and cannot be identified at first glance, specimens should be sent to a laboratory to have the specific identity determined.

In caged-layer flocks it is important that the birds are checked on a regular basis.

Spraying of birds is the best choice for most practical means. Birds should be treated twice on a 7-10 day interval. Care should be taken when spraying to ensure that the whole bird is treated, as it is common for lice to move to the neck from the vent when populations are large.

In houses, the egg-laden feathers will be a source of re-infestation and when the house is depopulated, a thorough cleanup should be completed.

Many lice are resistant against the commonly used products, so testing of efficacy is recommended.

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