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Roundworm Infection

Nematodiasis, Ascaridiosis, Helminthiasis, Helminth Infection, Nematode Infection

Roundworms (also referred to as nematodes) are a type of parasite that lives freely in the chicken's intestine, feeding off of the partially digested intestinal contents.Ascaridia galli is an important species of roundworms found in chickens.

How do chickens get roundworms?

Chickens get roundworms by pecking at or consuming feed, pasture, or water that is contaminated with feces from an infected bird (which contains microscopic roundworm eggs).
Ascaridia galli life cycle in chickens

Consequences of roundworms

Since roundworms eat the partially digested food in the chicken's intestinal tract, if there is a large number of roundworms present, they will rob the bird of vital nutrients. This has the biggest impact on young, growing birds because it deprives them of nutrients needed for them to grow. It can also cause problems in adult birds with compromised immune systems or under a great deal of stress.

Clinical Signs

Undigested feed in feces
Reduced appetite
Decreased growth
Pale comb/wattles


  • History
  • Clinical signs
  • Fecal exam
  • Necropsy


Citrus peel ethanolic extractFeed additive - 600-1200 mg/kg for 14 daysA Abdelqader et al., 2012
Garlic (Allicin)2.5 mg/bird
Drinking water - 1.5 mg/L of water daily for 5 days
F Velkers et al., 2011
Turmeric (Curcuma longa) root extract200-600 mg/kg of body weightAlrubaie Al, 2015
AlbendazoleAdministered orally, ¼ cc (mL) per bantam, ½ cc (mL) per large breed. Repeated in 2 weeks.G Damerow
Fenbendazole (liquid)3 cc (mL)/gal in water for 3 daysG Damerow
Fenbendazole (paste)Pea-size dose/bird, administered orally. Repeat in 10 daysG Damerow
Fenbendazole (powder)1 oz dissolved in 1 cup (240 mL) of water, mixed with 15-20 lb (3-4 g/kg feed) for 1 dayG Damerow
Ivermectin (drench or injectable)Administered orally - 1/4 cc (mL) per large breed chicken, 6-7 drops (0.1 cc) per bantam.
Administered in drinking water - 4 cc (mL)/gal of water, for 2 days.
G Damerow
Levamisole (drench)Administered orally - 1/4 cc (mL)/lb body weight.
Administered in drinking water - 10 cc (mL)/gal for 1 day. Repeat in 7 days, and repeat again in 7 days.
G Damerow
Levamisole (injectable)Injected under the skin, 1/4 cc (mL)/s lb body weight (25 mg/kg).G Damerow
PiperazineAdministered orally - 50 mg/bird (under 6 weeks of age), 100 mg/bird (over 6 weeks of age) or according to label. Repeat in 7-10 days.
Administered in drinking water - 3 cc (mL)/gallon of water, or according to label. Repeat in 7 days.
G Damerow



  • Maintaining good sanitary practices; since the eggs take 10 to 12 days to become infective once shed in droppings, if the droppings are removed then it reduces the chances birds accidentally consume them.
  • Occasionally providing apple cider vinegar in drinking water (20ml/L of water), however only should be used in non-galvanized drinkers.
  • If the birds are confined to a pen outside, rotate access to different areas regularly (once a weed) to minimize build up of worm populations
  • Discourage birds from eating off of the ground - Elevate feeder and waterer to discourage fecal contamination and clean and disinfect equipment daily.
  • Segregate birds by age groups, with particular care applied to sanitation of young birds
  • Chickens should receive a diet which includes supplementation with vitamin A and B complex vitamins. Lack of these vitamins makes the birds more susceptible to worm infections
  • Conduct routine fecal tests

Scientific References

Good Overviews


Age Range

Young chicks less than 12 weeks old are more susceptible. Chickens build a resistance with age.

Risk Factors

  • Keeping birds confined in one area on a continuous basis without rotating pasture lots.
  • Feeding birds kitchen scraps
  • Smaller birds, due to their body weight differences
  • Unbalanced diet
  • Use of a deep-litter bedding system

Also Consider