Ethiopia’s poultry sector, like the other livestock sectors, is transitioning from traditional backyard systems to more intensive commercial production, presenting challenges in feed quality, consistency, and cost. Soybean meal (SBM) is the most preferred protein source in poultry diets when available; however, supply variability, rising costs, and limited data on its nutritional consistency in Ethiopia necessitate evaluation of its quality and the exploration of alternative protein sources. Meanwhile, the recent expansion of soybean production and edible oil processing, particularly in the Amhara Region, which accounts for approximately 39% of national output, has established the region as a major processing hub and an important source of SBM. Despite this potential, the nutrient composition of Ethiopian SBM remains poorly characterized and can vary depending on processing methods, among other factors. Full-fat soybean (FFSB) has emerged as a protein- and energy-rich alternative that can reduce feed costs, but its use is limited by antinutritional factors such as trypsin inhibitors, which require roasting to improve nutrient availability and enhance laying hen performance. The need to develop cost-effective, nutritionally balanced rations using locally available feed resources underscores the importance of this research. This research is aimed to (1) assess the variability in the chemical composition of locally processed SBM, (2) determine the optimal SBM inclusion level in layer diets, (3) evaluate graded inclusion levels of roasted FFSB, and (4) examine the feasibility of partially replacing SBM with roasted FFSB in Bovans Brown laying hens under Ethiopian conditions. The chemical composition of SBM samples from 11 regional processing plants was first analyzed. Subsequently, three separate 12-week feeding trials were conducted using 120 Bovans Brown hens (34 weeks of age) in a completely randomized design, with each treatment replicated three times. The first trial evaluated SBM inclusion levels using five dietary treatments containing 15%, 20%, 25%, and 30% SBM, along with a commercial control diet. The second trial assessed graded inclusion levels of roasted FFSB (0%, 10%, 15%, 20%, and 25%). The third trial examined partial replacement of SBM with roasted FFSB using five dietary treatments: 100% SBM (positive control), 25%, 50%, 75% FFSB replacement, and 100% FFSB (negative control). Laboratory analysis revealed significant (P < 0.05) variation in crude protein (38.42–43.52%), ether extract (1.23–5.27%), crude fiber (5.58– 7.35%), and metabolizable energy (3348.3–3594.8 kcal/kg DM), between SBM samples from different processing plants in Amhara region. A dietary inclusion level of 20% SBM appears to be optimal, resulting the highest numerical hen-day egg production (89.72%) and net return (446.63 ETB), with no adverse effects on egg quality and hematological parameters remaining within normal ranges. Different inclusion levels of FFSB reduced egg production (53.03-63.57%) and feed efficiency (3.07-3.37 FCR) compared to the SBM diet (89.73% HDEP and 2.06 FCR). Although feed costs decreased with increasing FFSB inclusion, lower egg production reduced economic returns, making full substitution of SBM economically unprofitable. Partial replacement of SBM with roasted FFSB (25-75%) maintained hen-day egg production (HDEP), egg mass, and feed conversion ratio (FCR) comparable to the control, with the optimal appears to be in 25% FFSB replacement diet, which achieving the highest HDEP (79.67%) and egg mass (47.44 g/hen/day). However, complete replacement reduced egg production, body weight gain, feed efficiency, and profitability. In conclusion, the observed variability among the sampled Ethiopian SBM sources suggests the need for further multi-location and repeated assessments to better characterize national nutrient variation and to generate the evidence required for future development of country-specific feed composition standards for the Ethiopian feed industry. A 20% SBM inclusion level is suitable for mid-laying hens (34–46 weeks of age), and roasted FFSB can serve as a partial substitute at replacement up to 75%, with optimal results were observed at 25% partial replacement, However, complete replacement of SBM with traditionally roasted FFSB is not recommended until the roasting temperature and heating duration have been optimized and validated to effectively reduce anti-nutritional factors and improve nutrient utilization.