My 4 Month Old Golden Retriever (english Creamer) Has Bouts

my 4 month old golden retriever (english creamer) has bouts of diarrhea. I give him rice w/chicken and he gets a solid stool and then as i introduce his food (natural balance, puppy formula chicken, brown rice and duck meal) with the rice mixture he starts with the loose stool and diarrhea. he was treated for round worms within the last month