For what reason? As long as it's an all stages food it doesn't matter. In fact, a rotation of kibble that agree's with your pup each with a different protien source is a good way to go. Avoiding allergy development due to over use of one protien. This is not alway's easy though due to some of our pups sensitive tummies.Skyboxers\";p=\"52074 said:I have always believed not to change them until 1 year.