Could be coccidiosis or giardia, have you been to someone else's yard or have someone who has dogs come onto your yard?
no.... not that I can think of... I mean ive been around some buddies dogs lately hunting, but haven't been anywhere near their kennels. and I really don't mess with my puppies much. feed water, make sure everything looks healthy and leave them alone.
come to think of it last time I was around someone elses kennels was when I brought both of these pups home about a month ago. I got both of them from a buddy