Aggression.. maternal? or something else?

Question
We have two female sibling mixed breed dogs. They are about 8 years old. About 5 years ago they began to pick fights on occasion. Some times one would start it.. sometimes the other. Neither dog is spayed. We also have a young Rott female.. picked up off the street about a year ago.Last spring one female sibling became pregnant. She showed obvious and expected aggression toward the other dogs. So kept her isolated to the best of our ability until long after the pups were born and all but one (a Male) were given away. For a brief time all the dogs seems to get along. But a few months ago the mother dog began to attach the younger Rott.. totally unprovoked. She has done moderate damage. So we began to keep the Rott separate from the others. EVERY time this mother dog comes in contact with the Rott, she attacks.. without hesitation.. she obsessively stalks the door to the room where the Rott is often kept. Last night.. in a mild "skirmish" , the mother dog attached and seriously injured her sibling. We separated them.. waited for the tension to calm.. But the moment they came in contact she did it again ..Totally unprovoked.(She was muzzled at this point so no damage was done)..My question.. is there ANY chance at all that having the mother dog spayed will correct this behavior? We can by no means afford to have her "rehabilitated". It's only now we have the funds to even consider getting her spayed.
This dog has been in our family and is deeply loved for over eight years. Euthanizing is not something  we will consider lightly..

Any Advice would be Greatly appreciated.

Rebecca

Answer
Hi Rebecca,

Spaying a female will not give you the same benefits of neutering a young (6-8 month old) male. But absolutely get her spayed. There are many agencies that offer low or no cost spay coupons.

You may not be able to afford rehabbing her, but it does not have to be expensive and left untreated you will live a life of sequestering with closed doors waiting to be accidentally left open. Muzzling only creates frustration and possibly heat stroke if on too long when they are agitated.

There are rescue organizations that may have someone on staff to help or possibly rehome if that is possible. Most will not take on dogs with known aggression, but that does not mean you hide that information.

In the mean time, reduce the stress wherever possible. Do not set them up to fail with the very human hopefulness "But the were doing OK" or "they don't do it all the time"

You can also go to www.dogwise.com for books or ccpdt.com to see if there is a trainer in your area that might be able to help.