It seems we have many new members here, and some are wondering how to switch a dog from their old food to a new one. The best way for the dog is slow and easy.
First mix 3/4 old food with 1/4 new food, and feed that for four days to a week (if there are no problems with gas or runny poops, do the shorter time).
Next, mix 1/2 and 1/2, feed that another four days to a week (again, if no problems, the shorter time).
Last, mix 1/4 old food with 3/4 new food, and feed that for the next four to seven days.
After the last mix, your dog should be used to the new food, no matter how different it is, well enough to go on it solid.
If at any time your pup has diarrhea during the transition, step back to the previous mix for a few days and see if that settles things down. Some dogs are more susceptible than others to changes in diet, or to specific ingredients.
Jackie, Champ, and Buddy