As my reply to this oft repeated mantra would, unlike the post itself, undoubtedly once again be viewed as offensive

, I shall pass. However on the subject at hand I would add that the controversy as to whether adding calcium, adding calories, and/or adding protein to the diet of growing dogs contributes to (by causing 'overgrowth') or prevents ( by providing needed additional nutritional necessary for proper growth) such conditions as hip dysplasia, osteochondritis dessicans, or panosteitis has been a bone of contention for at least the past 40 +years without resolution.
I recall many years ago when i was in veterinary school Dr. Lennart Krook strongly advising that all large breed dogs receive calcium supplementation to prevent hip dysplasia while many were arguing just the opposite. The jury is still out. And people on both sides are very adamant, with many years of study and hundreds of links to support their arguments.
So the breeder's contention may have merit, but remains in the 'unproven' category. Recommending adult food based on her experience with her puppies should neither be considered 'right' nor 'wrong' advice. As with most subjects in nutrition, the only people we should strongly take issue with are those who feel that they know the 'one revealed truth.' - Dr. Mac