I'm not sure what size tub your are using but I use the black mortar tubs from Home Depot and I only keep 2 females in each tub with litters. I rotate 1 male through the tubs so the most they have is 3 adults at a time. I feel like this is the absolute most I would keep In a single tub. Especially as most of the tubs can have 20-30 babies at a time in them.