than you buy the mother rat but if the baby rats are young than get them all. that way you have a mother rat and baby rats to look after.
A baby rat's parents are typically referred to as the mother rat and the father rat.
So long as those baby rats are all boys, yes, but it should be taken slowly, as some adult males will kill baby rats.
after growth
no
after a year, when the next baby is born
They never leave their mother, their mother is the queen of the colony and they stay with that colony their entire life
Yes, when rats are born they each come attached to their own placenta, which the mother then licks off and eats. There is one placenta for each baby rat, but if the mother rat doesn't expel the placenta it can rot inside her and make her sick even to the point of death. Baby rats are connected to their placenta by their umbilical cord. Sources: I breed and research rats=)
At 6 days old, baby rats should still be nursing from their mother. If the mother is not present or unable to feed them, you can try using a suitable milk replacer specifically formulated for baby rodents. It's important to consult with a veterinarian experienced in rodent care for guidance on feeding and caring for such young rats.
Rats have about 6 to 18 babies every 23 days unless you sperate them, i recommend it, because its a lot on the mother.
it can leave 6-8 weeks
They never leave them. They stay together until death.