Abstract
Background:
Newcastle disease (ND) is the primary constraint on local chicken production in family poultry farming systems in Niger. During epidemic periods, producers commonly resort to locally available resources to manage the disease.

Aim:
This study aimed to evaluate the efficacy of the infusion of neem bark (Azadirachta indica) in water for treating ND.

Methods:
Eighty local chickens were allocated across two experimental sites. The chickens were further divided into four treatment groups within each site. Each group received ad libitum access to drinking water containing neem bark treatment for 2 weeks. The treatments consisted of T0, T13, T26, and T39, corresponding to 0, 13, 26, and 39 g of neem bark per liter of water, respectively. The data collected included feed intake, live weight of chickens, disease prevalence, and mortality rates. Statistical analyses were performed using R software. Orthogonal polynomial contrasts were applied to evaluate the linear and quadratic responses to the different doses of neem bark for treating ND. Survival analysis was performed to determine mortality.

Results:
Indicated a general decline in feed intake and live weight across all groups. The disease prevalence increased, but without significant linear or quadratic effects (p > 0.05). Throughout the experiment, the disease continued to spread and affected the health of the chickens. Mortality averaged 71.3% during the experiment period.

Conclusion:
This study underscores the importance of using traditional vaccines as the main approach to prevent disease outbreaks. No therapeutic benefit was observed from using neem bark in chicken drinking water for ND treatment.

Key words: Local chickens; Neem bark; Newcastle disease; Niger; Treatment.