Male Rat Fertility

[hhw]

How old does a male rat generally have to be to be a reliable breeder? I currently have 3 males; 2 are a high quality lab line and 1 is a normal. However, so far only the normal has fathered any litters. The lab males are around 3 months old I'm guessing, so they've definitely been sexually mature for more than 3 weeks, but so far nothing.

I've heard that males can take up to 6 months before they'll breed for you reliably? I just wanted to see what other people's experiences are in this area.

P.S. I'm now on litter #5, and litter #2 is currently being fed off. Woohoo!!! Hopefully, I'll soon be able to produce enough to have some leftover in the freezer. I just want to get my lab lines going though... My 2 lab males are already much bigger than the normal male, and I have a feeling that the line is high yield.