If a female dog bred with 2 males, what would the litter look like?

AS Luka has pointed out it IS possible for different pups to have different sires. there HAVE been cases where breeders in breeds with a limited number of pet home have does this on purpose - and NOT uncommonly the litter ends up sired by ONE stud! Timing may be the critical determiner but it is NOT always the first stud that sires the litter!