Having 5 dogs myself, I've come across all kinds of problems with my dogs who are outdoor dogs as we live in the countryside.
We used to have them chained up in front of their dogs houses as we have a small road running past our house and with 4 of our 5 dogs being sheep dog crossbreeds, chasing cars is one of their favourite pastimes. Twice a day, we would take them for a walk up the road.
Eventually, we splashed out on an electronic fence and receiver collars for the dogs and for the last year or so, the dogs have been able to run around outside together. This turned them into a pack.
While they've been enjoying their freedom, they've established a more pronounced hierarchy among themselves which can be quite difficult to deal with at times. Food fights would be the order of the day unless the human top dog takes firm control of the situation, but even with keeping a watchful eye on them wherever possible, there are still vicious dog fights at times.
The saddest thing that happened was that the pack ganged up on our cat last autumn and pinned her down. They hadn't injured her when I ran out and picked her up, but the cat suffered such a shock that she died from the traumatic experience some 30 minutes later. I'm still grieving for her 9 months later.
I've read Jan Fennell's book "The Dog Listener" and watched her video. Learned a lot from her but not enough, I think.
With watching Cesar Millan, "The Dog Whisperer" on the telly now, I feel that I might be able to sort out some of the problems I'm experiencing with the dogs. Especially one of them, a spayed 5 1/2 year old bitch, is very difficult to deal with and causes a lot of aggrevation with her aggressiveness.
After watching Cesar Millan, I've started trying to get to the bottom of her problems. She acts aggressively toward the other dogs and tries to establish herself as the new top dog (her mother, the current topdog, is getting a bit old now). At the same time, she is disobedient, but I think that she's insecure and doesn't fully trust the human top dogs. I've just ordered one of Cesar Millan's books to help me and I hope that I'll be able to rehabilitate her by myself.
We've started trying out some of Cesar's methods on our dogs and they appear to be working. Fingers crossed!