The study investigated the nutrient and phytochemical composition of blue-green algae (Spirulina platensis) as a potential feed for Boschveld chickens. The Official Methods of Analysis (AOAC) were used for nutrient composition determination whereas Quadrupole Time-of-Flight Mass Spectrometer (QTOF-MS) was used for the phenolic compounds. The moisture content of the algae was 3.33%, Crude Protein 21.63%, ADF 57.01%, NDF 69.58%, ash 13.27%, and fat 0.76%. The nutrient components of blue-green algae as determined in the study, exceeded the recommended minimum nutrient requirements for chickens, except for fat, whose composition was below the recommended level. Macro mineral composition of the algae was Ca 0.23%, Mg 0.11%, Na 0.16%, P 0.07%, and K 0.21%. The macro-mineral composition of blue-green algae as determined in the study exceeded the recommended minimum requirements for chickens, except for phosphorous (P) and potassium (K) whose compositions were below the recommended levels. Micro-mineral composition of the algae was Fe 8979ppm, Zn 25ppm, Cu 8ppm, K/Ca+Mg 0.26%, and Mn 25ppm. The micro-mineral composition of blue-green algae as determined in the study exceeded the recommended minimum requirements for chickens except for phosphorous and manganese whose composition was below the recommended level. Phenolic compound analysis indicated an abundance of gallic acid, phenolic acids and flavonoids. The findings of this study revealed that blue-green algae are rich in nutrients and diverse phenolic compounds that are essential for the production of indigenous chicken breeds.