Breeding Ratio for Feeder Mice

What are your breeding ratio? I read some labs would have 1:1 1 male to 1 female, 1:3 1 male to 3 female. While some breeders would have 3-5 females and I read on forum some pinkie "factory" would have upwards of 15 females to 1 male. What is the most you have heard work? I can not imagine 1 male to 30 females, it would be non stop work for the male? Not to mention the size of the tank/bin.

For food production that is consistent I do 1.3 or 1.4, you can put more females but the chances of them becoming pregnant will be lower and lower, not to mention that over crowding leads to stress and stress leads to cannibalism.

I cut way back on my mice because I ramped up on my rats, much less smell. Right now I run one male mouse per two females and rotate the male to a new tub every couple weeks. Right now I'm working on growing up replacement breeders as they are all getting a bit old (about 7 months old). Usually they are too old to breed at 10 months and usually only live 12 -14 months.

I guess I'll stick with 5 it seems to take a male 2-3 days to impregnate a female and to.... reload.