Go as far north of macfarlane as possibe and then west there are trees on top of a hill over a traintrack tunnel. Yesterday i found fox after fox after fox, probably killed 10 of them before i got bored.
Directions are pretty weak but when i get home in a few hours i can mark it on a map if you want.
I found the best fox-hunting area; it's just south of Armadillo, there's a slight rise. Put some bait on the ground and hide behind a rock. Foxes always seem to come in groups of two, while Coyotes come in bigger packs.
The only thing that ever appeared for me in that spot were Wolves, Foxes, and Coyotes, so you don't have to contend with the cougars or anything else. I got my quota of foxes there pretty easily.
Oh, yes - just be sure NOT to use a shotgun or Buffalo Rifle on them, because if you do they're completely destroyed and you can't skin them.
Raccoons and Skunks aren't too hard; you can find them around Armadillo itself at night. They seem to spawn often by the stagecoach and the alley near where you met Irish. Just keep taking a look around. I found Raccoons to be rarer than skunks.
I just shoot them in the face repeatedly. If I have a Winchester, and they have a face, I'll win.