Domestic dogs that run in packs will kill for the fun of it. On the other hand, packs of feral dogs kill for both food and fun.
We have a new policy now at our ranch and the neighboring ranches as well. If you see a stray dog, it's getting a dirt nap.
About 3 weeks ago, my neighbor had a $5000 show calf killed by 4 dogs. 1 of them was his own dog that joined the pack while it was attacking. 2 were shot on site. The other 2 were shot a couple days later.
He figured since there were 4 dogs, total will be $1000 per dog in restitution. One neighbor agreed to pay for his 1 dog. The other neighbor that had the 2 other dogs told him to pound sand.