Wow, it bothers me to hear that they actually do hunt in packs. When I hear them yipping and yowling at night I've comforted myself with the thought that if they did anything, it would only be one going after something really small, a cat or a chicken. My horses have lots of room to room to run, minimum of 1 1/2 acres, depending on which pasture they're in, and hopefully the two of them fighting together would drive off any pack. But one side of two pastures borders my neighbor's, and is bob-wire (neighbor had it up long before we moved in.) The horses leave it alone so we haven't replaced it, there's been so much to do getting 2 other pastures ready. Hopefully it was just that the cow got tangled up somehow and they moved in on something already helpless. We've been here 2 1/2 years and this is the first we've heard of coyotes killing something so large.