when is a luperci too old?

[Soran Aatte]

I actually did some research on this when I was working out how old to make Soran's youngest litter, I think at 8 they're still viable, the only information I could find on it was that a female dog at eleven could get pregnant but it was a huge risk to their own health and often the pups were all stillborn. But it would be possible before the age of ten I suppose they could have a litter so long as they took it easy.

(Hope you don't mind me throwing in my two pence/cents)