There may have been no abuse but simply the owner didn’t know how to take command of them. They are animals. If the lead dog didn’t respect their owner, he’s kibble. The other dogs will follow what the lead dog does.
The owner should be the lead dog (pack leader).
Yes, they’re animals. They still operate according to rules. Their rules, but rules regardless.
The pack leader doesn’t randomly kill pack members. If he did, he would find himself in a single dog pack very soon.
A dog that doesn’t think you’re the leader won’t necessarily kill you, he will attempt to dominate you. If you attempt to fight with him, then he might carry if further. And as soon as you submit, he will break off his act. He won’t rip your head off. These are the rules of the pack. Without them, there would be no pack, there would just be a big group of dogs fighting and humping.
You’ll look hard and long to find a dog that will KILL its loving, gentle master, for no reason other than wanting to be alpha. It doesn’t work that way in the pack. Two dogs don’t tie their paws together and knife fight...animals know it is far safer to put on a display and gain dominance that way than going to the lengths of a real fight. Real fights end up with real wounds...real wounds can kill you real quick in the natural world. Animals know this, and instinctively avoid fighting. They also don’t kill pack members, even ones lower than them, for no reason. Try keeping order in a pack that is randomly murdered by its leader...good luck with that.