My dog aledgedly bit my nabors dog through a fence they own, but there is no evidence, can we fight this?

What? No evidence? If a dog has a bite on its nose and the only dog that could do it is yours, that is evidence. Once a barrel landed on a man's head. There was a barrel maker on the second floor. There was no evidence the barrel came from the barrel store. Who do you think lost the case?

What are they asking for in terms of damages? The vet's bills? If possible, try to keep it private. Although your homeowner's insurance may cover this sort of claim, try to keep the matter private, or your premiums may increase dramatically. In addition, once your dog has a history of biting, all future claims will be easier to prove. Dogs are considered to be personal property, so you are liable and not the dog so to speak. You may also be in violation of city and state laws that govern vicious dogs. The other owner may file a complaint against you, which is another reason to try to settle the matter yourself. Your dog could even be destroyed pursuant to court order for a violation, but this is extreme. I hope your dog is licensed, for failure to license is another violation. Make sure your property is secure as well.