Small-scale poultry make a substantial contribution to food security and poverty alleviation in the livelihoods of resource-poor and highly vulnerable households in low-income, food-deficient countries. The emergence and spread of infectious diseases, including zoonoses such as the highly pathogenic avian influenza A subtype H5N1, can result in extreme economic losses and risk public health. Conventional decontamination measures are not feasible in resource-limited rural settings. Alternative cheap traditional methods, such as wood ash, are used to manage and control diseases in family poultry production. This study investigated the antimicrobial properties of wood ash in varying forms. Wood ash efficacy was determined in vitro on three distinct categories of disease agents in family poultry: bacteria, virus and parasites. Wood ash from red gum (Eucalyptus camaldulensis) was the test material. Varying concentrations of wood ash lye (0.1%–100%) were measured for antimicrobial efficacy on E. coli and avian influenza virus (AIV) at 2.5, 5, 7.5 and 10-minute intervals. Also, pH values for the corresponding concentrations were determined. Wood ash lye (WAL) was found to have a pH 11.64 at a concentration of 10% and pH 12. 93 at a concentration of 100% . The pH of WAL at 100% concentration remained constant 12 months after preparation. Wood ash in powder form (WAP) could not inhibit sporulation in unsporulated oocysts of mixed Eimeria species after 96 hours at 0.1, 1 and 10% (w/v) concentrations. WAL inhibited E. coli growth at a pH 11.94 at a concentration of 20% after five minutes’ exposure, whereas it could not inactivate AIV, even after 10 minutes’ incubation. The results suggest that WAL may be a suitable alkaline antibacterial agent to potentially contribute to low-cost disease control intervention strategies tailored for small-scale poultry to improve production and public health.