This study investigated the effect of supplementary L-Arginine on the growth rate and morphometrics of three indigenous strains of chicken. A total of 297 12-week-old pullets comprising 99 Kuroiler, Sasso, and Shika Brown each. A 3x3 factorial trial was used and each treatment was replicated thrice. There were three levels of L-Arginine oral inclusion (0.00mg, 500mg, and 1000mg/3000ml of water) for each treatment and replicate respectively. Morphometric data measured were body weight (BW), back length (BL), breast girth (BG), comb height (CH), shank length (SL), thigh length (TL), wattle height (WH), wattle length (WaL), wing length (WL). The linear body measurements showed no significant (p>0.05) differences. However, birds administered with a higher (1000mg) dosage of arginine had nominally higher metric values compared to the other treatments. The Kuroiler had higher linear measures among the breeds. These were comparable to the Sasso but differed from the Shika which had the least linear body measures. Observed trends showed that the morphometric traits were higher for the interaction between 1000nmg arginine administration and Kuroiler than any other combinations. There were reversals and deviations from the above-reported trend in the Shika breed for BW, BG, and SL while other traits were similar.