One hundred and sixty, 1-day old broiler chicks were  grouped into 4 equal groups,  at the 10^th day birds of  groups 1- 3 were  s.c  inoculated with 0.5 ml containing y  1.5x 10⁸ of  S.xylosis, S. sciuri and S.lentus; respectively and group 4 was noninfected control. Clinical signs in infected groups started at 2-3dpi as general signs. Signs disappear in Ciprofloxacillin treated subgroups 24 hr post treatment and lasted to the 7^th day in non treated. Average body weight gain in S.xylosis infected non treated was the highest (813.90 gm), followed by S. scuiri  (778.50gm ) and 773.75  in S. lentus infected treated . FCR was the highest in control (1.69 treated  and  1.74 non treated) followed by   S. scuiri  infected (1.81  non treated and 1.82 treated) and the lowest 1.94 was in S.lentus infected non treated. S. sciuri was reisolated from intestine and spleen (5^th dpi) and from intestine (7 and 10 dpi).  While  S.lentuswas reisolated from intestine , liver and spleen (3^rd dpi) ; from intestine and spleen (5^th dpi) and  intestine (10^th dpi). Histopathological lesion was recorded in infected group as hemorrhages with sinusoidal dilation, focal areas of vacuolar  degeneration , fatty degeneration and shrinkage of hepatocytes in liver,  necrotic changes of lymphocytes and vacuolion of corpuscle in  spleen. Leucocytic infiltration , degeneration and necrosis of epithelium surface  and intraepithelial as well as submucosal leucoytic infiltration were seen in intestine.  In conclusion the injected organisms induce mild subclinical disease with recording of histopathological lesions in liver, spleen and intestine.  This  area needs more investigation to explore pathogenicity of CoNS in chickens.