Okay so i have a 6 Stack Breeding rack System with home depot tubs, i have 3 males but i really wanna get rid of 1 or 2 of them, and i want to have 3 females in each other tub but one of the males is a Butthole and fights until the other is bloody so i have him in a seperate tub, so thats 2 outta 6 tubs used for males

Okay ive breed and had some success after i knew what i was doin, so i have 3 sisters getting raised up to be breeders together in one tub,
In the other i have there mom alone she used to be with others but one was really old and the other died during birth, so shes alone for now,
then i have 2 hairless and 1 daughter W/hairless gene,
and another tub with 2 Random Females that have been together for about 2 months now, i got 2 rats off someone who didnt want them anymore so i put them together with a hairless gene Female, one of the Free rats died Unknown why, so now i have just the hairless gene and free together for now untill i have more grown up breeders

So my real problem is that my Two Hairless had a litter, at least im pretty sure it was both of them, cuz i counted and there was 12 with some dead ones, and then i counted again and found 5 more dead ones and the live total up to 13, so i kept a eye on them but they kept dying

i was thinking it was cuz they were all in the same spot, it looked like they either couldnt get milk because there was so many fighting for milk or they got stomped or crushed or something cuz they looked weird. and when i looked the next afternoon there was only 6... and they werent eating the babies all of the dead babies were on the bottom of the pile

so i took the remaining and put them and 1 of the females into a steralite tub with a water bottle.

Does anyone know why this happened and how to stop it from happening again because im spending a fortune on Feeders.

i heard that most ppl just have 3 females and 1 male in a tub but i just reuse the same male or 2 cuz i thought there was a risk of the males eating the babies and getting the mom preg before the pups weened

so im just so confused as to how to fix this problem, i really dont want to make a new rack that only holds 1 Pregnant rat per steralite tub, i just dont have the room,

i just want three females in 5 tubs and 2 males in the sixth tub and for the females to be able to breed without getting a ton of dead pinkys

Thanks in advance for all your help
Jamey