Puppies grow so quickly and I love watching them gain more confidence and explore their surroundings. 
As they grow and move they can be prone to developing some minor problems that can have the potential to cause some long term effects. I find that on chiropractic (veterinary spinal manipulative therapy) assessment, about 50% of the young puppies will have some minor issues (their spine, ribs, sacroiliac joint) that are very fixable!
To NOT fix such things, I believe puts the puppies at risk of growing abnormally. For example, a pain in the 'hind end' (sacroiliac joint) could cause the puppy to stand and move differently (it certainly does for me!) and subsequently could grow with a 'roached back.'
I routinely recommend that the puppies have a chiropractic assessment at 6-8 weeks while still with the breeders, prior to going to a new home or on placement in their new home. Routine chiropractic reassessment every 3 months for the 1st year while they are growing so rapidly will help get them off to a healthy start.
Pawsitive Strides Veterinary Rehabilitation and Therapy