Effects of synbiotic, probiotic and prebiotic supplementation on alterations in haematological parameters of broiler chickens infected with Eimeria tenella was understudied. Ninety-day-old broiler chicks divided into 6 groups (I, II, III, IV, V, VI) containing 15 chicks each were used for the study. Group I served as negative control (non-supplemented, unchallenged). Group II served as positive control (non-supplemented but challenged). Group III was supplemented with prebiotic (sugarcane molasses). Group IV was supplemented probiotic (Antox®). Group V was supplemented synbiotic (Enflorax®) whilst Group VI was given Amprolium prophylactic treatment. Birds were challenged at 21 days with 2.0 × 104 sporulated E. tenella oocysts/chick. Blood samples were taken on days 0, 4, 7, 11 and 14 post-challenge for haematology and serum total protein evaluation according to standard laboratory procedures. Results showed haematological alterations even 4 days post-challenge (dpc) in infected groups. Total leucocyte count rose 4 dpc and was significantly (P < 0.05) high 7 dpc. Heterophil/lymphocyte ratio was significantly high in the infected groups compared with negative control by 7 dpc. Relative monocyte and oesinophil counts also increased significantly (P < 0.05). Packed cell volume, haemoglobin concentration and total erythrocyte counts were significantly lower in infected groups 7 dpc. MCHC and MCV were also low. Serum total protein equally decreased 4 dpc and was significantly (P < 0.05) lower in the infected groups compared with negative control 7 dpc. Supplementation with synbiotic, probiotic and prebiotic products amended haematological alterations associated with experimental Eimeria tenella infection more rapidly and lessened fatalities prompted by caecal coccidiosis. © 2021, The Author(s), under exclusive licence to Springer-Verlag London Ltd., part of Springer Nature.