I feed my two on JWB with a bit of Nature diet mixed in. They don't get too many treats but quite a few rawhide chews as Jovi is a right chewer...
I don't get to see Neo's so much as he's goes in the middle of the mead lands privately, but Jovi is quite similar, dark poo hard at first and then they get softer and yellower as they go along (more tan colour then canary yellow). From what I've seen of Neo's poo he's the same too.
I don't usually worry too much, although Jovi does eat quite a few things he's not supposed too (anything made from wood) and I'm always retrieving things from him he shouldn't have, so I just keep an eye on it from that perspective.