At 3-4 weeks of age I put 40 rats and 3 mothers into a shared cage with food and water.

Their weights were from 40-60, most being in the 40-50 gram range.

One week later the lightest weighed 75 grams, and the heaviest was 110 grams.

Milk + all you can eat food = good I guess The mothers would all lay down and nurse once or twice a day that I noticed. Trying this again. For how little the mothers nurse in this situation I think it is almost as good as staged weaning, but a little easier.