Hey! Is it definitely poop? It looks a lot like wet grass pellets from their food, sometimes piggies like to alternate between their water bottle and dry food, soaking it in the process. I've had a reasonable amount of soft poops (well, the piggies, not me!) and they're a soft paste rather than what is in your dish.
If it's definitely poop, hold off on veggies and see a vet. Lots of hay and access to fresh water as soft poops can cause dehydration, which can become serious quite quickly in small pets.