The effect of early supplementation of a processed soy protein product (PSP) and its route of application for broiler chickens was studied. A total of 252 day-old male Ross 308 chicks were randomly placed on 4 treatments as: (1) control diet" (2) control diet + PSP paste (PSP1)" (3) diet with 100 g PSP/kg only (PSP2)" and (4) diet with 100 g PSP/kg + PSP paste (PSP3). The PSP paste was withdrawn after 5 d, while the starter diets with or without PSP were provided until day 10. Each treatment was replicated 7 times, with 9 birds per replicate. On 10 d, birds on 100 g PSP/kg plus PSP paste consumed the lowest feed, while body weight gain (BWG) and feed conversion ratio (FCR) were not affected by the treatments. On day 35, birds on control diet had significantly (P < 0.05) lower BWG and FCR than the treatment groups with feed intake unaffected. The dressing percentage of broiler carcass at slaughter was significantly improved by the supplementation of PSP in diet or as paste. The ileal digestibility of nutrients was not affected by the treatments, except for potassium, which was better utilized by birds fed the control diet plus PSP paste. Early supplementation of PSP in diet and as paste can be beneficial to growth in broiler chickens. The PSP paste may be beneficial for use in in-hatchery or on-site early feeding systems. The values of PSP as a dietary supplement are well known but this is the first insight into its application as a paste.