We have a few that are crossing with feral dogs, but the coyotes here are getting bigger and bolder on their own. Plenty of food sources, lots of cover, very little interference, so as they evolve into the niche here (the wolf population was decimated when the elk was wiped out, allowing the increasingly aggressive coyote population to overwhelm it and finish it off), they're becoming bigger and stronger.
Even at 40 - 50 lbs., even a smallish pack coyotes is more than a match for a domestic Rottie, Lab, GSD, Doberman, etc. that's never been blooded, let alone killed. I've come to realize that most domestic dogs are SO domesticated that they just aren't hard-wired for the kill anymore; the coyotes are.
We're seeing more people with wild donkeys and llamas here, too, but the problem with that is you MUST have the donkeys altered -- they breed like rabbits, and you'd better not let your dog get into the field with them, they don't differentiate between coyotes and the family pets.