Personally I don't have any problems. I usually put 3 nursing females in a tub, after 2 weeks I remove one mama and put it back in breeding and the other 2 divy out the babies. Sometimes after another week or so I will remove another mama leaving one to nurse the 3 litters until they are weaned which is usually the following week. While in the tub together most of my mamas seem to work together raising the young.