cannon fodder
From Longman Dictionary of Contemporary Englishcannon fodderˈcannon ˌfodder noun [uncountable] ARMYordinary soldiers whose lives are not considered to be very important, and who are sent to fight where they are likely to get killedExamples from the Corpuscannon fodder• If all three aspects are not addressed the 240 additional cannon fodder will not remain in the system either.• Children will be cannon fodder to boost a school's image.• Between them the eight runners had won three races; they were racing's cannon fodder.