May want to make the females in smaller groups. as most females will have their litter in the same pile in the cage which in turn causes many to not get fed and they die. I learned my lesson when 5 females had a litter over night in same tub and well i found 6 dead on the bottom of the pile
I keep 3 females per tub and put a male in with them for 1 week then take them out after the week is over to go to the other females. Once females are pregnant my males go back to thier main tub in the rack and rest till their needed again.