NAIROBI (Reuters) - Kenya s election commission said polling stations had opened in the much of the country on Thursday but voting had been hampered by  security challenges  in a number of places where voting would be delayed until Oct. 28. Wafula Chebukati, head of the election commission, said areas where voting would be delayed included Homa Hay, Kisumu, Migori and Siaya - all in the opposition stronghold of western Kenya. 