While some amounts are to be expected, there should be more positive feelings than negative ones. If the kids are fighting for the parent's attention, the best solution is to withdraw. Stay out of the way and refuse to be involved. They will find something else to do.
Kids also pick on each other out of boredom.
If there is a lot of uproar about nothing, the kids are probably bored. Turn off the TV and give these kids work to do. If they get too tired to fight, they won't fight. Sometimes siblings honestly cannot stand one another. If the argument is a rehash of a long held grievance, the kids are in a genuine conflict situation probably caused by different perspectives or different personalities.