not necessarily. im sure there is a all natural brand. or you can just make it your self. chicken stock + water + salt. and boil. its pretty basic stuff.
for example this lo sodium one looks good http://www.amazon.com/Campbells-Sodi.../dp/B000H136GM canned items dont require preservatives, thats the purpose of the can, and MSG additive generally isnt used. and is more or less harmless. the salt factor of the MSG is what i d worry about.