Babies on the way!

[Lolo76]

I've had my breeding trio of mice for over a month, and was starting to wonder if they were doing anything... then today one of the girls came out (they're usually hiding - only the boy is friendly), and she is HUGE!! I picked her up to feel her belly, and it's just full of little mice. The lumps still feel quite tiny, so I'm not sure how long until she gives birth, but she does look incredibly fat & pear-shaped. So when should I expect to see babies, and is there anything I need to do in preparation?

FYI: They all live together in a small cage with two wooden "houses," exercise wheel, water bottle, etc. I use Carefresh bedding with a little shredded paper mixed in (they love nesting with it), and feed a diet of mostly commercial mouse food w/ some treats... usually just sunflower seeds, nuts, plain cereal, and maybe a little bread. Is that all okay once the babies come? And is it safe to leave the male with them? I only have one cage for now, so he'd otherwise have to live in a critter keeper - which I know he would hate, especially without his beloved running wheel. Also, since I feed mostly live & need prey of varying sizes, should I leave all the babies in the cage until they're ready for feeding? TIA for any advice on my first litter!