We feed our Morgan (will be 13 weeks old on Tuesday) Fromms Puppy Gold (in the pink bag). When he became part of our family at 8 weeks, he was on Purina Pro Plan/Puppy/Focus which, like the Iams, isn't the best food out there. For the first weeks, we didn't make any food changes. We figured he was under enough stress with a twelve hour car ride from our breeders home to ours, plus leaving everyone and everything he had ever known. Then, very slowly, we began mixing the Fromms in with the Purina. (1/4 Fromms to 3/4 Purina for 5 days, then 1/2 of each for 5 days, then 3/4 Fromms to 1/4 Purina for 5 days, then all Fromms) We went very slowly to avoid any tummy upsets. Funny thing ~ Morgan would actually try and pick out the Fromms and leave the Purina. We will eventually transition to one of the 4 star Fromms all life stages foods when Morgan is a little older. Personally, I would not wait to begin transitioning to a better food. This is an important time developmentally for your little one. I, too, had 90% of a large bag of the breeder recommended food that our local animal shelter was delighted to receive. We also give Morgan NuVet supplements... he thinks he is getting a treat :-) Isn't having a bully just wonderful?