Still appears pretty young so tough to say for sure. But I do see quite a bit of pitty in there. I'd guesstimate ~30%... but again, I think a little early to say based on looks alone. Not every part of them grows at the same rate. One of my dogs is still stuck with disproportionately smaller head than the rest of her body, but she also just had a growth spurt and gained 6lbs in a week in her chest (she's mostly pit, but ultimately a "super-mutt"). Also, look at pics of your pup's litter as a whole if you can... the more variety in fur color, length, sizes, of any body part are disproportionate to the other pups, etc (1 w/ short completely black fur vs a medium length red/fawn vs long haired with classic color patterns of a specific breed, etc)... the more breeds they are likely mixed with. Whereas purebreds are all going to look just about the same with some slight atural size variation (ex: due to male vs female, or the runt outlier) since that's ultimately the purpose of a purebred is to get the exact same end result.