Abstract
Background:
Capillaria infections pose a significant economic threat to domestic backyard poultry.

Aim:
This study aimed to evaluate the epidemiological, pathological, and control of Capillaria infections in domestic chickens.

Methods:
Four hundred and fifty-six faecal samples were collected and transferred into clean, sterile, labelled bottles containing 2.5% potassium dichromate as a preservative. The samples were analysed with the direct smear and centrifugal flotation techniques for the detection of Capillaria eggs under a microscope. Forty-five naturally infected, 30-week-old backyard chickens were selected based on their egg per gram (EPG) count and divided into three groups (A–C), which were housed separately. Group A was untreated, while Groups B and C received oral Mebendazole and a Mebendazole derivative compound at doses of 15 mg/1.5 kg for three days, respectively. Faecal samples were collected on days 7, 14, and 21 post-treatments to assess the reduction in Capillaria egg counts in the treated groups. Data were analysed using R (2025) for percentages, chi-square tests, univariate and multivariate analyses of associated factors, and ANOVA on drug efficacy.

Results:
Overall, 39.9% of samples were infected, with higher prevalence in females (43.1%) than males (35.4%), older chickens were more infected (47.4%) than younger chickens (27.5%), and weak (76.8%) compared to healthy chickens (24.0%). Seasonal variation showed the highest infection rates in summer (54.4%) and spring (54.0%), and the lowest in winter (25.2%) and autumn (26.3%). Extensive rearing, muddy housing, and pond water use were associated with significant infection rates. Deworming and biosecurity had significant impact (P<0.05). Infection risk was notably higher during the wet season. Histopathology revealed oedema, glandular hyperplasia, inflammation, necrosis, villous atrophy, and epithelial shedding linked to Capillaria spp. Infection. Treatment significantly reduced Capillaria egg counts, with Mebendazole moderately lowering eggs, while the derivative compound eradicated them by day 15, maintaining zero counts through day 21. (P<0.05).

Conclusion:
Capillaria infections in backyard chickens causes diarrhea and lines results reduction in meat and egg production in poultry farming system. Therefore, it is recommended to improve management practices by maintaining hygienic conditions, conducting regular screening, and using anthelmintics for the control.

Key words: Capillaria; Poultry farming; Parasitosis; Economy.