I fed Pro Plan Puppy to my male lab until he was about 10 months old and really flourished on it. His coat was beautiful, energy excellent, stools seemed perfect and he gobbled it up with enthusiasm.
when it was time to get off the puppy formula, I switched him to Dr. Tim's Kinesis. He never really ate it with the same enthusiasm and about 2 44# bags after the switch he started smelling funny, almost like a puppy smell only much stronger. And then he started really feverishly licking/chewing at his rear. I suspected anal gland issues so took him to the vet and sure enough, his glands were very full and had to be manually expressed. Now, a few weeks later, he's starting to get that smell again and licking around his rear again and I'm wondering if it could be that the food isn't agreeing with him? He has gotten to where he won't touch the food for hours some times, which is unusual for him and is eating grass more and more.