22% - 24% is actually pretty decent for a breeding/nursing female and a troop of wild babies.
For feeders it’s a lot.

Excess protein, can lead to scabs, hair loss, kidney failure if you want to produce healthy feeders you need to make sure your breeders are provided with and healthy diet, you do not want your breeders to die prematurely.

Some of the best lab blocks on the market, designed for feeder animals usually average 16%-18% in protein, which is way, enough for a nursing female, and also for pups when they start eating on their own.

I have females that I have acquired in May last year that are still STRONG breeders for their age averaging 10 babies (18 month is the average age for menopause in rats), younger females usually average 14-16 babies not to bad for females that would have nutritional deficiency due to a low protein diet

A good diet will help your breeders stay healthy and produce nice healthy litters.