When they're further into weaning, don't be afraid to seperate the kittens from mother for a couple hours a day.
That way the kittens learn to be a bit more independent, and mother gets a break from the kittens.
Mothering cats can get rather bored/annoyed of their kittens not too long after they're born, and if the kittens keep pestering the mother she can get angry and hit them.
Don't be surprised if they fight a lot later on in life, particularly when the kittens are done weaning, around 8 weeks old or so.
Mother will basically forget that they're her children, and vice versa.
But she'll still probably be the matriarch, and put them in their place. That's how my cat was with her children.