I've never dealt with mice, but I've had countless hamster litters in my lifetime and it's gotta be pretty similar. I'm not sure if you *have* to separate her from the others, but I do know that you *can* (ie the father doesn't play a role in childcare), so I recommend isolating her from the other mice just to play it safe.
Give lots of fluffy bedding... a little bag of Carefresh will do the trick.
Make sure she's got a good supply of food and water. Giving some extra nutrition by sharing healthy table scraps is a good idea, too (veggies, fruits, etc.
This site might help you find safe options.).
For the most part, just leave her alone. First time moms might kill/eat the litter or they might be amazing moms. You never know, but either way they don't need any human intervention
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