I'm lucky enough to have the entire set, but hooves do appear to be one of the rarer ones, because I've got 4 accs, 9 manes, 5 backgrounds, 9 coats, 12 tattoos, but only 2 hooves.
And yeah, note frequency has died down a bit for me. It's definitely closer to one every 10 mins for me now. But, I'm not complaining as I've had a lot of fun hunting, and have a good haul of traits and gold. :)