Hi Ange M-
The best thing you can do is find a food that states it is for a large breed puppy. Now I will warn you, some that make this claim are not actually large breed puppy safe because the company formulating the food doesn’t actually understand what causes developmental issues in growing LBPs on the diet side of things. Holistic Select was a really good example of a company like this.
The companies that are going to have the most trustworthy large breed puppy foods are Purina, Science Diet and Royal Canin. There is no reason to “avoid” any ingredients in a puppy on the assumption that maybe just maybe, he could one day develop a food sensitivity. This is absurd and will only cause you to be more confused. There is also no need to feed a puppy a rotational diet as suggested above. If something does happen, it will be almost impossible to know the cause. I went through this myself, so I can no longer recommend rotational diets.
