only daily care i give mine is feed them and check water bottles to make sure they wont run out while I'm not around (i dont like putting all my mice on the same water supply cause if 1 gets sick cause of bad water or what ever they all get sick with water bottles you get the biggest size even for 21 mice it lasts a few days unless the ball is touching something and leaks then if disease breaks out you are sure it wasn't spread to all the mice from a central water supply)
as for smell i put a cup of kitty litter under the aspen so it dont stink unless i go 2 weeks between cleanings (like going on vacation just have somebody come and check food and water daily)
Jeremy78 wasn't it you you posted a vid of a big communal nest of babies more then 2 females worth of babies.
i know i pull pregnant mice out and put them in cages with other females around the same due time up-to 4 females. where as long as all the females are there together from the get go help take care of each others babies and don't fight or eat each others babies. I've had females that still had a week left till they had there babies feeding her cage mates babies