Hi Amy-
Since most Labs will reach over 50lbs at mature weight they are considered a large breed puppy. This means that for optimal growth they need to be on a food specially for a large breed puppy. Merrick puppy food is not designed for the growth of large breed puppies, so I would say it is a blessing in disguise that he will not eat it.
Developmental orthopedic disorders do not develop due to high levels of protein in the food. This is a myth that was laid to rest some 20 years ago. What we do know now is that excessive dietary calcium and over nutrition (fat puppy) along with genetics are the leasing causes of common bone growth issues.
The challenge with finding a large breed puppy food is that not all of the companies “large breed puppy” foods meet the criteria for what a food for a growing LBP should be. Many are in excess of calcium. This means you must call or email the company and ask for a nutrient analysis of the food and double check it against the calcium calculator on this site.
