1: mix 25% new diet with 75% old diet.
week 2: mix 50% new diet with 50% old diet.
week 3: mix 75% new diet with 25% old diet.
week 4: your pet should now be switched over to 100% of the new diet.
if your pet is completely avoiding a new food, that means it is not hungry enough to try the new diet. keep in mind the size of your pet's stomach is often smaller than you think. whatever your normal serving amount of food, cut that serving in half while your pet is transition to a new diet. this method will allow them to be hungrier and more willing to eat 