Prevalence of Select Intestinal Parasites in Alabama Backyard Poultry Flocks

Quick Look

This Alabama field study tested fecal samples from backyard poultry flocks and found that intestinal parasites were common. Coccidia were detected in 64.1% of flocks, Capillaria eggs in 26.6%, and Ascaridia or Heterakis eggs in 20.3%. The practical message is not to panic or blindly medicate. It is to understand that parasites are common in small flocks and that fecal testing can help owners make better decisions.

Study at a Glance

Species: Backyard poultry, mostly chickens with two turkey samples

Breed/Line: Backyard flocks in Alabama

Number of Birds/Flocks: 84 fecal samples from 64 backyard flocks

Study Duration: Summers of 2017 and 2018

Country: United States

Journal: Animals

Year: 2021

Research Focus: Intestinal parasite prevalence in Alabama backyard poultry flocks

Study Overview

The researchers collected fecal samples from backyard poultry flocks across Alabama and tested for several internal parasites. The study was designed to give better information for extension and outreach programs, because backyard poultry owners often need practical parasite education.

This paper matters because parasite conversations in backyard poultry can swing between ignoring the issue and over-treating everything. Data gives us a steadier place to stand.

How Was the Study Conducted?

Owners submitted 84 fecal samples from 64 flocks during the summers of 2017 and 2018. Most samples came from chickens, with two from turkeys.

The researchers used fecal testing to look for coccidia oocysts and nematode eggs, including Ascaridia or Heterakis and Capillaria. They also used PCR testing on one sample per flock for Histomonas meleagridis, Tetratrichomonas gallinarum, Cryptosporidium species, and Blastocystis species.

Key Findings

Coccidia were the most commonly detected parasites. Eimeria oocysts were found in 64.1% of flocks and 59.5% of samples. Most counts were relatively low, with a median of 800 oocysts per gram, although some samples were much higher.

Roundworm-type eggs were also detected. Ascaridia or Heterakis eggs were found in 20.3% of flocks, and Capillaria eggs were found in 26.6% of flocks. Median egg counts were low, below 500 eggs per gram.

PCR testing detected Histomonas meleagridis in 4.7% of flocks and Tetratrichomonas gallinarum in 18.8% of flocks. The researchers also detected organisms with zoonotic relevance: Cryptosporidium species in 18.8% of flocks and Blastocystis species in 87.5% of flocks.

Strengths of the Study

This study is useful because it focuses on real U.S. backyard flocks rather than only commercial poultry. It gives owners and educators numbers to work with when discussing coccidia, worms, and other intestinal organisms.

It also used more than one testing approach. Microscopy helped identify oocysts and eggs, while PCR allowed detection of organisms that may not be found the same way under a microscope.

Limitations of the Study

The study was limited to Alabama flocks and summer sampling. Parasite pressure can vary by region, season, housing, stocking density, soil conditions, sanitation, and whether birds free-range.

Fecal testing also shows what was shed in the sample. It does not automatically prove that a detected organism is causing disease in that bird or flock. Clinical signs, flock history, age, environment, and repeat testing may matter.

Poultry Nerds Takeaway

Internal parasites are not rare in backyard poultry. Coccidia and worm eggs showed up often enough in this study that flock owners should include parasite management in their prevention plan.

That does not mean every flock needs constant medication. It means owners should learn the signs, keep bedding and runs from becoming chronically wet and overloaded, avoid overcrowding, rotate or rest ground when possible, protect young birds, and use fecal testing when parasite problems are suspected. These steps belong in a broader practical backyard biosecurity plan.

For sick birds, poor weight gain, diarrhea, pale combs, repeated losses, or suspected zoonotic exposure, work with a veterinarian or diagnostic lab. The best parasite plan is based on evidence, not guesses.

Original Research

Authors: M. Carrisosa et al.

Paper title: Prevalence of Select Intestinal Parasites in Alabama Backyard Poultry Flocks

Journal: Animals. 2021;11(4):939.

DOI: https://doi.org/10.3390/ani11040939

Original publication: https://pmc.ncbi.nlm.nih.gov/articles/PMC8066009/

Open-access version: https://pmc.ncbi.nlm.nih.gov/articles/PMC8066009/

How to Cite This Review

Poultry Nerds. (2026). Prevalence of Select Intestinal Parasites in Alabama Backyard Poultry Flocks (Research Review). Poultry Nerds Research Library. Retrieved July 19, 2026, from https://www.PoultryNerdsPodcast.com/research-library/prevalence-of-select-intestinal-parasites-in-alabama-backyard-poultry-flocks

Research Review

This article summarizes a peer-reviewed scientific publication and explains its practical application for poultry keepers, breeders, and educators. It is an original review written by Poultry Nerds and is not a reproduction of the original manuscript. Readers are encouraged to review the complete publication using the original publisher and open-access links provided above.

This review is for education only. It is not a diagnosis or treatment plan. Poultry owners should work with a veterinarian or diagnostic laboratory for sick birds, unexpected deaths, suspected zoonotic disease, or possible reportable disease.

Continue Exploring Poultry Research

Browse the Poultry Nerds Research Library for more evidence-based reviews.

Read Causes of Mortality in Backyard Poultry in Eight States for a broader look at diagnostic findings in small flocks.