We haven't had a problem with coyotes stalking our dogs, since the dogs are only outdoors on their own in daylight, in an enclosure, if at all. Normally they are with me and/or the wife, whether indoors or out.
However, we have coyotes in the area, and the things are huge. We recently moved from Georgia, where coyotes were maybe 35-50lbs, to NW Missouri... I mistook a coyote for a fawn, at first the other day, as it jumped out of a ditch near the road, as it was that tall - but it became immediately clear it was a coyote.
Two days ago, I saw a lone coyote in my west pasture, and I'd estimate its size as German Shepherd. Two of us saw it (a gentleman who was delivering our horses was with me), and it was definitely a coyote - although at first I thought it might have been a neighbor's dog.
I've never seen coyotes this size; they look like small wolves.
Finally convinced my wife to carry a 442 when she tends the horses at night, though - she saw one of the beasts the other day.
I'm not too worried that they will do anything, but on the other hand, if they do, these things are big enough that ONE would pose a threat, let alone a pack.