Good Guess! On his side he does have three punctures high and one low. Perfect for a large owl.. Plus the lack of broken bones suggests it might not have been a bite attack with violent shaking... I know when my coon dog grabs a coon, all you can hear is bones crunching. Yep.. I change my opinion to bird of prey also.
Those owls are some nasty sumbitches. When I was a kid and my dad raised pheasants, he use to set foothold traps around the perimeter for the coons. We caught a great horned owl on three separate occasions. Let me tell you, that sucker was MEAN! Let it go twice.... he never showed back up again after the third time, for some reason.... :smiley_chinrub:
I don't know if there are any eagles near where your buddy lives, Mntr... but I've seen those go after dogs too. My grandma lives up by Sandusky Bay, and I watched one swoop down and try to snatch one of her chihuahas out of the front yard. The fact that you said this happened in the evening leads me to believe it was a great horned owl, though.