Hairworm or Threadworm (Capillaria spp.) in Birds & Poultry

Hairworm or Threadworm (Capillaria spp.) can infect Chicken, Ducks, Turkey, Pheasant, Partridge, Quail, Goose and Pigs. They are 1-1.5cm thin and threadlike, one of the smallest but most dangerous poultry parasites, with several species, each invading a specific region of the digestive tract. Although one of the less common parasites we see in poultry, they are of concern because of the severity of disease they cause.

They have a 2-8 week direct or indirect lifecycle* depending on the species. Earth worms are the intermediate host - reduce damp areas in coop to prevent infection.

poorly chicken


Symptoms includes diarrhoea, anaemia, weight loss, loss of appetite, depression and dullness. It is a severe pathogenic disease and can cause haemorrhage and thickening of intestinal walls, poor absorption of nutrients and stunted growth.


Capillaria infections show up reliably on worm egg counts. Because of the pathogenic nature of this parasite, any indication of infection warrants treatment.


Because of the severity of disease these parasites can cause we recommend treatment if any eggs are seen. Flubenvet is an effective treatment.

*Directly = from the ground/floor Indirectly = via an intermediate host such as an earthworm, snail or insect which has eaten the eggs.