I have had a similar experience with Xerxes, my 5 month old. His back legs points out instead of straight when he walked so I took him to my vet. He asked what I was feeding him. I said, "Natures Balance Ultra." He said," Get him off of it. This puppy is getting way to many nutrience and he's growing way to fast." So I backed him up to Purina adult at his recomondation. He said," Check back in 6 weeks and let me know how he is doing." I was sweating bullets, afraid it was hip displasia, even though his parents have excellent ratings.