Hi,
Unfortunately, you probably will never be able to tame these birds as long as they share a cage. When you have a pet bird, you are the bird’s companion in place of it having another bird as a companion. But when two birds share a cage they have each other and will almost always bond and will not have any interest in a human as a companion. It’s unusual for a budgie to be so aggressive, especially the male. Possibly these birds are older than you were told. And usually the females are more likely to bite. These birds sound more like a bonded pair than a young pair. I can give you the links to our behavior and training pages, but again, these birds are going to be more interested in being together, and will focus on protecting each other from you.
Their diet is a much bigger concern. Millet offers almost no nutrition, so basically these birds are malnourished. Seeds should be offered as a rare treat in very small amounts. You should be feeding a nutritionally balanced diet like pellets, along with leafy greens, veggies and some fruit. I’ll also provide the link to our page on what to feed your birds. I’m sorry you were not properly informed on having a pet bird and feeding one. A single young budgie is the best choice when you want to try to tame a bird.
Pet Bird and Parrot Behavior
Teaching Your Bird
Bird Food Guide
Thank you for asking Lafeber,
Brenda