If you don't know what kind of parasite there may be then it's best to do Safeguard 5 days in a row. If you instead get Valbazen, then you can do two doses 10 days apart to get most parasites. Valbazen dose is .5 ml for a standard sized bird. (actual math is birds weight in lbs / 2.2 x 20mg / 113.6)
Most of the time you will not see worms in the droppings. Sometimes if there are tape worms you will see segments, or if they have a heavy load of roundworm they might pass one, but most of the time the worms live their entire lives inside the bird. The eggs from the worms pass in the droppings and the eggs are microscopic, not visible with the naked eye. If you can get a fecal float test done, that looks for the eggs.
Most of the time you will not see worms in the droppings. Sometimes if there are tape worms you will see segments, or if they have a heavy load of roundworm they might pass one, but most of the time the worms live their entire lives inside the bird. The eggs from the worms pass in the droppings and the eggs are microscopic, not visible with the naked eye. If you can get a fecal float test done, that looks for the eggs.