It is not unusual. Perhaps you are meaning it a bit too well with them? (According to the intro thread, the piggies are mature adults from Windwhistle Warren).
Guinea pigs need only about 50g/1 cupful of mixed veg per piggy per day (in as many servings as you like); preferably containing one veg high in vitamin C, like a slice of pepper, some broccoli, a sprig of fresh coriander/cilantro, parsley, dill, mint or basil.
Adult guinea pigs also only need about half to a handful of pellets, not the unlimited quantity of a still growing youngster.
Up to 80% of the daily food intake should be hay - that keeps the guts stable and the crucial back teeth ground down.
And of course, fresh water daily; preferably without any additives.
I chop my veg and feed it and the pellets in separate bowls. Mine get their pellets twice daily, each in a separate bowl, so that every piggy gets enough.