Growth performance of broiler starter chicks fed diets containing 0, 25, 50 or 75 g/kg of RCK were investigated in a feeding trial set up as a completely randomized design with four treatments, replicated four times and lasting 28 days. Broilers were finished on a common finisher diet containing 150 g/kg of RCK and growth parameters were compared after eight weeks to determine if there were any residual effects of the diets tested up to four 4 weeks. There were no significant differences (P>0.05) among treatments in growth performance (growth rate, total feed intake, feed conversion ratio). Cost of gain was, however, significantly different (P<0.001) with the control feed (0RCK) being significantly (P<0.001) more expensive than the feeds containing RCK. At the end of eight weeks, none of the experimental feeds fed in the starter phase appeared to have given any group of birds a comparative advantage. It was concluded that RCK could be included in broiler starter feeds up to a level of 75 g/kg without any deleterious effects. The need to look at optimum levels of inclusion for broilers and other classes of poultry was emphasized.