He is young. I would run a fecal at the vets. I would also go to a bland diet as well (rice and cooked meat).
With my older dogs I tend to wait a day or so to see if it resolves with a bland diet. With my pups, I usually go straight to a fecal/call the vet. I would also make sure you don't just switch kibbles cold turkey.
Leyna vom Grunenfeld, HT, PT, HSAs, HRDs, RLFs
SG Paisley vom Kirschental
, JHD, aka "the devil"
Toby vom Kirschental
, 3/21/14, aka TJ
Levi vom Grunenfeld, RIP 9/5/04 - 3/4/13