The Davainea or small tape worms have an indirect life cycle, infecting the chicken through eating slugs and snails containing the cysticeroids (immature parasites).They are considered to be the most pathogenic of all tape worms.They are made up of up to nine segments with 80-90 small hooks arranged in rows on the head. Tape worms are uncommon in barn or cage kept hens because they dont come into contact with the intermediate hosts.
Symptoms include: diarrhoea and wasting. On examination of a dead bird there may be some thickening of the intestines and signs of bleeding. The worms are only 1.5-4mm long which makes them difficult to see.