We have a 2 year old Pom/terrier mix and a 14 year old wire hair terrier, both females. We have had the younger dog since she was 6 weeks old and both dogs are spayed. In the last few weeks, she has started attacking the older dog and today she drew blood. When I try to separate them, she attacks me also. We are now putting her in a separte room from the rest of us, but don't want to continue to do this. Is there a way to stop her or do we need to give her to someone who has no other dogs? We also have a 10 year old male chihuahua but she doesn't bother him.
It's possible that the younger dog has decided she wants to be alpha. In some dogs (and some breeds in particular) there's a lot of tension between dogs of the same sex. NILIF may or may not work in this situation, but it certainly can't hurt. If you let the dogs interact with each other make sure you keep the younger female on a leash or harness, so you can yank her out of the fight without risking injury to yourself. Its my experience and opinion that you are most likely to be bitten by your own dog when breaking up a dog fight. Keep a water spray bottle filled with a 1/2 and 1/2 mixture of vinegar handy, and if they get into a tussle, the shock of the smell may be enough to break it up.
Be aware, it is possible that this will not resolve itself, that the fighting will get worse and worse, and that you may need to consider either rehoming the younger dog, or even keeping her 100% seperate from the other at all times ifyou hvae the capacity for it.