Just a strange thing going in in our original breeding trio of ASF rats. There are 1 male and 2 females which we got back in the summer of 2007. Both females have regularily produced litters though the one we call Big Momma is the more dominant female and has generally done the vast majority of the litter care for both litters.
Recently we've noticed that the only litters being produced are from the slightly smaller female (Little Momma). Big Momma is still doing the majority of the nursing and is still the more "mothering" of the two females. I know these were all young ASF's when we got them so I doubt it's an age issue. I'm just not sure what's going on here and why Big Momma has seemed to have stopped breeding.
She's not ill in anyway, acting completely normally for an ASF - she just seems to not be producing her own young lately.
I'm having trouble finding clear information on the breeding life of an ASF female. I understand they live about 2 or 3 years but I can't find anything definitive on how long they remain productive breeders.