Did you notice that the perches that came with your cage were all 1/2-inch dowels, and they’re extremely smooth?
Yeah. That’s not what we want.
See, your Gouldian’s feet get sores on them when they have to stand day in and day out on the exact same surface. So it’s best to give them varied types of perches –different lengths, widths, and different types of surfaces. You can find a lot: sand/cement covered, twisted wood, real wood branches fitted with screws to fasten them on. These are great because they get to exercise their feet.
I’m not saying don’t use the dowel perches, but add some other ones in addition to.
Just stay away from those sandpaper covers you can put over a perch, they’ll hurt them.
A few good perches: