The reason fro your budgie's problem is the lack of vitamins and minerals.
As a beginning take it to the vet to cut the growths and to file away the curved beak. Don't try to do this yourself - it should be executed by a specialist.
The next step is to buy a crayon with vitamins and minerals for it from the zoo shop. You also have to provide pine-tree twigs for it to gnaw. When there is no crayon you can replace it with chalk. It is absolutely necessary for the birds.
However you have to estimate whether the bristling up and the shivering don't come because of having cold. This can be estimated when examining its faecals. If the bird has a cold they will be either very dark or very light than normal. If these symptoms exist you should apply the following treatment:
Take one capsule tetraulean / from the chemist's /. Open it. Take some powder from the capsule on the point of a small knife. Dissolve this very small dose into 1-2 drops of water. After that open the beak and pour the liquid carefully inside with a dropper.
The treatment should be applied for 3 days most. After that the faecals will obtain their normal kind.
Be careful not to overdose the tetraulean.
Except for that even if the parrot has no cold you should compulsory buy vitamins for it from the zoo shop. Another reason for this condition of the feathery creature can be starvation because with a deformed beak it is most probable that the bird can't eat millet. And only vegetables and fruit is not enough.
Give bread to your budgies as they like it a lot.
Do not keep them in a very cold or very hot place. Let the temperature be normal. Budgies don't like humidity and draughts. This could also be a reason for deformations. And if it is possible let them fly at least a little
