Improved indigenous chicken contributes to the nutrition of farmers in rural communities. The use of maize as an energy source in chicken diets is becoming unacceptable due to competition from humans, resulting in high feed costs. Alternative energy sources like low-tannin sorghum can be grown in Western Kenya. The objective of the study was to determine the nutrient composition of sorghum-based diets and the growth of improved indigenous chicken in Busia and Siaya Counties. Dietary treatments consisted of 50% (T1), 75% (T2) sorghum inclusion, and control (commercial diet) (T3). Farmers on semi-intensive were provided dietary treatments, and free-range (T4) was not provided. Feed samples were subjected to laboratory analysis for proximate composition, amino acids, and tannin content. Growth characteristics were collected biweekly. Data were subjected to analysis of variance, and then means that differed significantly were separated using Tukey’s test in Genstat 14th edition. For proximate composition, dry matter was significantly (p<0.05) higher in T2 (91.9%) and T3 (92.1%) compared to T1 (91.4%). Crude fat was significantly (p<0.05) higher in T2 (9.54%) than in T1 (6.84%) and T3 (6.57%). The crude fibre was significantly (p<0.05) higher in T3 (14.3%) compared to T1 (3.37%) and T2 (3.62%). Crude protein was significantly (p<0.05) higher in T2 (15.8%) and T1 (15.2%) compared to T3 (12.6%). Metabolisable energy was significantly (p<0.05) lower in T3 (2723 Kcal/Kg) compared to T1 (3569 Kcal/Kg) and T2 (3684 Kcal/Kg). Amino acids (lysine, methionine, cysteine, and tryptophan) content in diets T2 and T3 were significantly (p<0.05) higher than T1. The tannin content of the sorghum variety C26 was 1.24%. T1 had a significantly high (p<0.05) mean final weight (970 g), body weight gain (804 g), daily weight gain (14.4 g), and feed conversion ratio (5.57). Mortality was highest at T4 (17.1%). It was concluded that the inclusion of 50% low tannin sorghum meets chicken feed nutritional requirements and is best for growth performance. The study recommended that farmers rearing chicken should plant low tannin sorghum to be utilized as feed ingredient to cut the cost of production