Capillaria spp, also called hairworms or threadworms, that are common type of roundworm in domestic poultry and wild birds. They are very thin, filamentous worms measuring 15-25 mm long (males) and 35-80 mm long (females).
Life cycle: Capillaria spp has an indirect life cycle, and produces eggs that can infect birds 4-6 weeks following passing in feces. Birds are infected by consumption of earthworms that are infected with the eggs.
Capillaria spp are often found in outside environments where birds are kept in a confined area with poor-drainage and ventilation. Birds are often fed off of the ground and have access to earthworms in the soil.