If they are fighting, then they need to be housed separately.
One lovebird, or one bonded pair of lovebirds per cage only.
It is not as common for lovebirds so young to be fighting, but it does happen. Some will fight in the brooder.
It is normal they will be ¨beaking¨ things at this stage. They are learning their beaks and exploring. If you get a nip, put the bird down on the nearest bird safe surface and ¨ignore¨ them for a minute. If you have smaller children, try to be sure they copy you and ignore the bird for that same time. This will teach the bird that you do not accept this behaviour and that doing so will result in being ignored, they don´t like that.
Don´t cage them or take them far, the nearest safe place to put them down quickly is the best place.
As for bites, If you see the bird with their feathers raised and beak open faceing you, don´t try to approach as they will bite and funnily the best way to teach not to bite, is to not get bitten. So try your best to get out of the way of bites.
How come they were raised from 6 days old? Was there a problem?