The Selenium Signal: Turning Free Range Immunity into a Playbook for Every Poultry Farm

By Tosin Clegg

Nigeria’s increasing demand for affordable animal protein, especially poultry, is an encouraged household nutrition and rural livelihoods. Yet, flock health and the economics behind a successful production ultimately depends on immune competence, shaped by both management and micronutrient status. In research published in the Sokoto Journal of Veterinary Sciences, Dr. Latifat A. Adekunle rigorously examined how rearing systems and trace minerals interact to influence disease resistance in poultry by studying sixty birds sourced from markets and poultry houses around Ibadan: intensively reared broilers and layers on formulated rations, and local chickens maintained under extensive, free-range conditions. Using atomic absorption spectrophotometry to quantify selenium and zinc and standard haematology for complete blood counts, her team investigated a simple question but with far-reaching implications: do differences in management translate into measurable differences in micronutrient bioavailability and, in turn, immune status? The answer emerged with clarity. Extensively reared birds were found to have higher circulating selenium concentrations alongside lower heterophil: lymphocyte (H:L) ratios, the latter a widely accepted biomarker of stress and disease resistance . In these local chickens, erythrocyte indices were higher, lymphocyte counts were elevated, and heterophil counts were lower than in intensively housed counterparts. The most consistent signal across management systems centered on selenium, plausibly reflecting differences in access to naturally selenium-containing plants, seeds, soil-borne invertebrates, and dietary diversity available to foraging birds. The findings align with established biology: selenium plays a significant role as an antioxidant, limits oxidative damage to membranes, preserves leukocyte function, and supports vaccine take and antibody production, especially under heat stress, and pathogen challenge common in tropical poultry systems.

The practical implications for Nigeria’s poultry sector are immediate. For intensively reared flocks that rely entirely on formulated feeds whose micronutrient profile drifts with grain source, harvest season, and storage conditions, selenium status should be treated as a managed input rather than a dietary accident: producers can request transparent labeling from feed mills, favor bioavailable selenium sources (for example, organic selenium yeast) paired with adequate vitamin E to maximize antioxidant synergy, and tune premixes seasonally to match periods of heat, peak lay, or heavy vaccination schedules. At the farm level, simple H:L monitoring in birds can provide a low-cost chat for stress monitoring before production metrics visibly declines. Industry and policy can scale these gains by standardizing premix disclosures, investing in extension training on blood smear differentials and H:L interpretation, and strengthening regional laboratory capacity to run basic complete blood counts and trace mineral panels, modest investments that prevent larger losses by catching downward trends early.

Crucially, micronutrient optimization complements, not replaces, the non-negotiables of vaccination, the strongest H:L profile cannot compensate for porous biosecurity. Taken together with Dr. Adekunle’s prior work on Newcastle disease and endocrine-driven calcium disruption in layers, this selenium, H:L evidence offers a cohesive, field-ready playbook: protect birds with vaccines and biosecurity, stabilize their internal milieu with bioavailable micronutrients, and track resilience using a practical, on-farm biomarker. Although grounded in Nigerian conditions, the biology is universal, making the approach applicable across breeds, climates, and production scales in other low- and middle-income settings. By properly investigating this long-noticed field observation, the study helps farmers reduce mortality, and improve profitability, while supporting national goals in food security, poverty reduction, and sustainable production that keeps pace with a rapidly growing population.