Sierra's reactivity - a question

Sierra has come a long way. Her comfort zone is much smaller, and we can walk past a dog on the other side of the street without incident. She looks to me for assurance when she sees another dog, all that good stuff. Off leash she has no problems with other dogs anymore, which is a HUGE improvement.

However, what should I be doing if the other dog barks at her first? (Like from behind a fence, or if the other dog is being walked as well and starts barking at her?)

She of course wants to bark back, and not nearly with the ferocity that her reactions used to be. I've been stopping her, but I'm thinking that's not really fair... should I let her bark in these instances, or is that only inviting escalation?

With Meg, who sounds a bit like Sierra in regards to her dog issues, I try to just call her away from the barking dog (assuming it is contained). Usually a "leave it" followed by cheerfully encouraging her to cross the street with me, walk backwards, detour, or whatever else I can do to put more space between us and the dog. Cookies come out if accessible to reward movement or head-turns towards me. If we are on a trail passing someone head on, I jog past, whistling for her to follow. Whether it is "fair" or not, I don't want to allow or encourage any barking or aggressing back at other dogs as long as they can't reach her. Focus on me, move along, and tons of rewards for it. She does great in just about any situation now except passing other dogs on leash who are reacting if she is also on leash. At this point, that is still a lot of trouble for her. Dogs behind a fence or tied have a finite point where they can't come any closer; her being off leash is much less stressful to her.

That sounds like exactly what I'm already doing. Distraction, treats, and lots of praise for eye contact and looking at me. Glad to know I'm on the right track

^^^That.

Dogs don't HAVE to bark when a dog barks at them. In fact, the most confident/secure dogs will not bark back. It's as if someone's yelling at you for no reason and you stay calm and say, "geez, what's all the fuss about? Just chill." It's hard not to yell back, but it can be done through self control.

Plus the barking dogs will just feed off each other and escalate the situation..... NOT good for a reactive dog.

I noticed that myself. My very confident dogs have always chuckled at the maniacs behind a fence or on a chain.

I have to agree with distracting Sierra with a look at me cue, or simply moving away from the other dog. Some offending dogs can be told to "sit", and they will. The sit or down stops the bark. The offending dog's reward can be a treat, but it can also be your dog walking away from him, which is what both dogs want.