Don't know about keeping them cold. I've bred the smelly things for about 12 months without problems at ambient temperatures.
If you keep them in cages, make sure that the cages have VERY small gaps! I found that when they are weaners (i.e. can run around) they are small enough to fit through the smallest gaps - mice all over the house!
I find it's best when they drop a litter, to put the mum and babies in an aquarium. Just be sure to isolate them from each other. They'll attack any mice that they haven't been living with! :shock:
Sometimes it helps if you move two sets of mums and pinkies into an enclosure that's new to all of them, as they haven't established a territory to defend.