7 year old aussies

Question
My male and female are becoming very aggressive toward each other it seems.  Really fighting over where they lay on our deck or front porch.  They (I dont know which one or if it were both) killed the neighbors small dog a couple of months ago but no one saw it so dont really know what happened.  I know they are territorial.  After this I purchased a wireless pet fence and they have 180 yards diameter to run.  Normally the female is more aggressive than the male.  They were both "fixed" as puppies.  I have tried dog beds but they always tear them up.

Answer
Hi Mindy,
Are these dogs littermates by any chance, or are they similar in age?  Often, same age dogs of similar status fight more than dogs that are separated by age, and by status.  If this is a sudden behavior change, do have a vet investigate.  Aussies can be subject to hypothyroidism, which has been linked to aggressive behavior.  They can also have vision problems, also sometimes a cause of sudden aggression.  So, do have the health screening done if in doubt.
I don't know what's going on because I can't see your dogs in action, but my guess is that you could benefit from hiring a behaviorist to come and help you.  (Animal Behavior Society or IAABC web pages will have listings).  Anyway, it is never my first choice to use "invisible" fence with Aussies, German Shepherds, or other breeds that tend to become barrier aggressive, or which are territorial.  If the object of their attention is of sufficient value to them, some dogs will just blast through the fence and go get it - not what you want!  So, best to have the side that faces "civilization" be blocked by a screening device, or by bushes or a solid fence panel.
Neutering often helps reduce dog to dog aggression in males, but has little to no effect, and may even make things worse, in females.  Not that you shouldn't spay your female dogs, but just FYI.
The one thing you don't want to do with any aggressive dog is to use aggression or harsh discipline, or try to support the dog you think is the dominant one (humans are often wrong about this, and it prolongs the fighting).  The one thing you DO want is for each dog to respect YOU.  So, IMO, classes for each dog, separately, and maybe a consultation with a local behaviorist, are what I would advise.  


I had a feeling they were littermates.  Unfortunately, we often see this, and it's one reason we don't recommend people get littermates.  If the fighting hasn't stopped, chances are that they are still vying for the spot of "top dog".  Life has to be pretty unpleasant for them if one is always getting "licked" by the other, or if the chaos doen't quit.  Sometimes, it's best to re-home one, only you can decide.  But, if they start to injure one another (draw blood), then that is the option I suggest.  If not, and they only have occasional spats with no damage, then just sib rivalry most likely.