Context. Blood and rumen contents, which are currently considered wastes in many abattoirs, could be valuable ingredients in poultry feeding; however, several factors including high fibre and low energy may limit their dietary inclusion. There is need for more research on feed processing and diet formulation to maximise utilisation of these by-products in poultry feeding. Aim. We investigated the effect on broiler finisher performance of feeding bovine blood, rumen digesta and vegetable oil concentrate as a partial replacement for soybean meal. Methods. Three isonitrogenous and isocaloric diets were formulated: a control diet based on maize and soybean meal, and two test diets. In the test diets, heat-processed blood-rumen digesta meal and vegetable oil concentrate replaced 50% of the soybean meal, with and without exogenous enzymes. Diets were allocated to five replicate pens containing six Ross broilers aged 21 days in a completely randomised design for a period of 21 days. Key results. Results showed no treatment effect (P > 0.05) on average daily feed intake but birds fed the test diets gained more weight (P < 0.05) and converted their feed more efficiently (P < 0.05) than the control group. Enzyme supplementation had no additional effect (P > 0.05) on growth performance. There were no dietary effects (P > 0.05) on relative weights of carcass and gut segments. Feed cost of liveweight gain and carcass weight was reduced (P < 0.05) on the test diets. Conclusion. Heat-processed blood-rumen digesta meal and vegetable oil concentrate can replace up to 50% of soybean meal in broiler fishier diets. At this level of replacement, enzyme supplementation is not required. Implications. The use of blood and rumen content in poultry diets has cost and environmental benefits.