hi
the reason most pups come out fawn is because wheaton terriers are that colour,there colour gene is not diluted with any other colours,were as greyhounds are not just one colour,there colour genetics are made up of different colours ie black/white,brindle white ,fawn/white,blue brindle ect.
i used to have a first cross wheaton/greyhound x first cross bull/greyhound,the father was pied black/white(bull greyhond) and the mother (wheaton/greyhound)was the typical fawn colour ,but all 10 pups in the litter was identical in colour!!! pied black/white broken coated .the answer to the ques