A trial was conducted to study the effects of the aromatic plant thyme, a commercial probiotic (Protexin) and avilamycin on broiler performance, blood biochemical parameters and also the antibody response to sheep red blood cells. A total of 750 broilers were assigned into five replicate groups for each of five dietary treatments, namely; control (C), 2.5 mg/kg avilamycin (AB), 0.1 g/kg commercial probiotic (P), 5 g/kg ground thyme (T1), and 7.5 g/kg ground thyme (T2). In general, body weight, feed consumption and feed conversion ratio were not affected by dietary treatments compared to the control birds (P>0.05). Birds fed the P supplemented treatment had the greatest serum protein levels (P<0.001) and highest albumin levels (P<0.001) when compared with control birds, while the birds fed T2 had the lowest (P<0.001). Dietary supplementation reduced (P<0.001) cholesterol and triglyceride concentration in serum of broilers, with the effect were more noticeable by P supplements. Moreover, blood calcium and phosphorus concentrations were higher (P<0.001) in birds fed the P-supplemented diet compared to the birds fed the control diets.This study suggests that probiotic supplementation in particular, and to an intermediate extent ground thyme supplementation in diets of broiler, resulted in chicks with favorably improved blood biochemical parameters and mineral utilization, compared to the birds fed diets supplemented with avilamycin or without any supplementation.