Avian vet Margaret Wissman says this: "Budgies and cockatiels consume a primarily seed diet in the wild, and they do seem to thrive on a seed-based diet. However, pellets, sprouted seeds, fresh fruits, vegetables, pasta, whole wheat bread and healthy table foods are sound additions to the budgie and cockatiel diet. Birds that eat just seeds should have access to a cuttlebone or mineral block, and should receive supplemental vitamins (but NOT in the drinking water). I recommend Nekton STM as a general vitamin supplement. It should be sprinkled on moist food. Some budgies and cockatiels are extremely resistant to dietary changes."
The full section about budgies on her great site is worth bookmarking for rereading many times as you get to know your two babies:
http://www.exoticpetvet.net/avian/budgietiel.html That last sentence about resistance to changes in diet is good reason to begin feeding them healthy food right now, while they're so young that your nutritious food will be what they both consider completely normal for life.
Enjoy!