Why my parakeets are like tat?

I had my parakkeets for almost a week they stopped biting now are biting again when my niece and nephew afterwards started touching em also before they didn't like each other now when I take them out to fly they have to be together. Also how do I tame them and the male one keeps scratching!!!! Himself. And opens his moth wide open for a sec alot!!!! They wont separate and they are babies and also the male keeps jumping on the femaless back????!!!!