A total of 96 guinea fowl hens (28-32 weeks old) were used to study the effect of photoperiod and dietary innovative materials (DIM) (Monk’s pepper and Thyme) on the haematological and serum biochemical indices of guinea fowl hens. The birds were weighed and randomly assigned to eight treatment groups in a 2 (two photoperiods) ×4 (DIM) factorial arrangement in a Completely Randomized Design (CRD). The birds were exposed to two photoperiods of 12 hours of normal light (12 L) and 20 hours of extended light (20 L) period using ECKO 100W solar LED lamp with an average light intensity of 5.78 lux. The four diets used contained 6g of monks pepper (M) and thyme (T)/kg diet in different ratios as follows No DIM, 50M50T, 75M25T, and 25M75T. Each treatment was replicated three times having four birds per replicate. Feed and water were provided ad libitum and after nine months, blood samples were collected for haematological and serum biochemical evaluation. The results indicated that photoperiod significantly (P<0.05) influenced White blood cell (WBC) count and monocytes content while DIM significantly (P<0.05) improved all haematological parameters measured except lymphocytes, heterophils and eosinophils. For serum parameters, birds on extended photoperiod had significantly (p<0.05) higher total protein, globulin and uric acid content but no significant difference (p>0.05) was recorded for albumin. DIM inclusion significantly (p<0.05) affected total protein, globulin and uric acid content. However, albumin content was not significantly (p>0.05) affected. It can be concluded that 12 hours of light and DIM at ratio 25M75T/kg diet improved the blood parameters and general health of guinea fowl hens.