This experiment was conducted in the field of laying hens affiliated with the Department of Animal Production at the College of Agriculture at Basrah University during the period from 27/12/2021 to 21/2/2021. It was applied to 90 experimental units (a 45-week-old laying hens) of Lohmann Extra, randomly allocated to five treatments. Each treatment has three replicates, with six chickens per replicate. The treatments included: - T1: Negative control treatment (basal diet without Addition) T2: Positive control treatment, the addition of dried skim milk at a level of 1 g / kg of feed. T3, T4, T5: add the manufactured bacterial preparation at a level of (0.5, 1, and 2( g/kg feed, respectively. To study the effect of manufactured bacterial preparation on some cellular and biochemical blood characteristics of laying hens. There was a significant (P≤0.05) improvement in cellular blood parameters, packed cell volume (PCV) and biochemical parameters of blood serum (cholesterol, total protein, albumin, globulin) in laying hens, and there were no significant differences in the ratio of heterophile cells to lymphocytes(H/L), glucose, and liver enzymes Aspartate Aminotransferase (AST), Alanine Aminotransferase (ALT).