If it was only one male floating through tubs? Then I would say you got stuck with a dud like I did at first.
Several of them has got to be a weird fluke.
If you're working with 3 females to a tub, I would honestly just cycle the male through every 2 weeks instead of keeping so many males with females.
You'll be feeding the males less and momma rats will get a small break between breeding which will keep the litter sizes up. Leaving the male with females gets them pregnant every 2 weeks if not sooner and they'll burn out faster as breeders.
Rats are usually great parents, but 1.3 in a tub and 30+ babies is a bit crazy. Even with just 3 females and babies in a tub, sometimes the smaller pinkies get crowded out and starve so you're loosing out.
How many snakes are you feeding?
I have 1 male for 5 tubs with 2-3 females each. I had to freeze off a few rats now that the production is finally going smooth.
I just change the tub the male is in every other bedding change and it's working smooth. Aside from one possible cannibalism issue...every litter is producing 12 at least for me.