Sometimes when a puppy is purchased, a breeder will tell the new owner that they need to keep the puppy on the same food for 6mths, I am sure this is simply because the breeder believes that the food they use is the best, and wants your puppy to do well, but healthwise there is no reason to wait to change your puppy over to a raw diet, infact, the sooner a puppy is changed over to raw, the better it is, as good nutrients, in their most bio-available form, are the best thing your puppy can get to help them grow fit and strong and have good healthy immune systems to build their natural immunity quickly and effectively.