The work evaluated blood and histological indices of broiler birds fed diets containing mango, watermelon and parkia seeds fermented using Lactobacillus plantarum. The experiment was carried out under the supervision of Microbiology department of Kaduna State University with the 4 set of diet containing; no fruits seed inclusion (T1) mango inclusion (T2) watermelon inclusion (T3) and parkia inclusion (T4). 96 birds were used for the experiment which was laid in Randomized Block Design (RBD) having 3 replicates with 12 birds per replicate and fed for 6 weeks after which blood sample was taken for analysis and birds slaughtered for internal organs evaluation. Result obtained showed blood parameter of broiler birds fed diet T3 had highest levels of PVC (78.3%), and Haemoglobin (26%) with impressive Lymphocytes (189%), Platelets (162.6 × 109/l) & Heterophil (13.66%) compared to birds fed the other experimental diets and also the internal organs such as lungs, heart, intestine, spleen, gizzard & kidney of the bird fed T3 diet were all Normal compared to birds fed the others diet. It is therefore concluded that the use of Lactobacillus plantarum in fermentation of watermelon lowered anti nutritional factors and gave broiler birds overall good health. It is therefore recommended that further research be carried out to ascertain the appropriate inclusion level of watermelon seeds that would give the best result.