First off, there's a finite limit on how big a wolf pack gets. You've got to balance a big kill (like a horse or moose) versus number of mouths to feed. Ten wolves is probably a good limit on the upper end.
Second, if you've got a donkey, you're probably going to have some dead wolves. Donkeys are used to guard sheep from predators. They'll kick and stomp a dog to death with a grin on their face.
Third, as Sheadakota says, the horse and donkey will know about the wolves way before the humans. The horse will be panicking way before the wolves show up to the humans.
Fourth is the horse will go away from the wolves. No way will it go any closer to the pack then it has to. And a horse can rival a mountain goat in ability to go places.
Fifth is if the horse was formerly wild, and has been well-trained, it might not bolt, but fight. I had a horse take on two German shepherds and reduce them to quivering masses. I had another horse that spent an hour chasing a dog around his pasture (dog was afraid of getting zapped by the fence again). The horse had a lot of fun. The dog a lot less so. If the horse is fresh and given some room, it's going to take out a few of the wolves too.
Wolf packs work on large prey by running them down, making them tired, before the attack. Otherwise, any of the large animals like cattle, moose, horses will do a lot of damage.
Best of luck,
Jim Clark-Dawe