Support! I only have one wolf that I know I definitely will never breed, but I'd find a toggle feature incredibly useful for having the breeding ability turned off, for my single wolves. That way wolves, that I've not yet found mates for, won't clutter up the wolf selection when I go to breed a pair.
I would also really like this. I have a wolf that's basically aro/ace and it seems like there isn't a confirmation for breeding. Plus I can see people not wanting to breed gen1 wolves, to preserve the lineage. I come from another breeding site that places great value on "unbred gen1s" and I can't imagine that won't be the case here for some as well.
Massive support! A toggle would be nice, especially to unclog the breeding tab for wolves that you'd actually want to breed/keep breeding. I have a good amount of g1 wolves that I would rather keep unbred and this toggle suggestion would be extremely useful for everyone.