The large roundworm, Ascaridia galli is the most common intestinal parasite found in backyard and free range chicken flocks worldwide. It is a yellowish white, thick worm which can grow up to 115 mm (4.5 inches) in length.
A. galli lives freely inside the chicken's small intestine. There, it reproduces and lays eggs, which are passed out of the chicken in their feces. Occasionally, adult worms will migrate into other parts of the chicken’s body, such as the cloaca, oviduct, body cavity, esophagus, crop, or gizzard. When in the oviduct, they can sometimes get trapped inside a newly formed egg.
A. galli Life Cycle: A. galli have a simple and direct life cycle. They are transmitted to chickens through ingestion of an embroyonated egg, shed in the droppings of an infected host. Once consumed by the chicken, the worm eggs hatch n the proventriculus or the duodenum of the chicken’s gastrointestinal tract. It takes 28-30 days for the newly hatched worms to mature into adults. The pre-patent period after infection is 5-8 weeks (when the bird starts shedding the worm eggs in their feces).
Survival in the Environment: Under optimum conditions of temperature and moisture, A. galli eggs can survive in the environment for up to 8 months, and become infective after passing through feces in 7-28 days. The eggs are resistant to low (nonfreezing) temperatures, but are killed when exposed to direct sunlight or dryness.