Males will breed as early as 5 or 5 weeks of age. Females should be about 250 grams which is generally around 4 or 5 months of age. Big healthy young females = easy birthing, lots of milk and a very nice litter of feeders.
Btw, it's not so hard to feed them off as they develop into pups. By then their own mother is so sick of them they'll try to hop out of the tub, stuff their belly against the glass trying to keep the "teat leeches" off them and heck, I had a female rat drop her pup in my hand...I think she was giving me the hint LOL





