My Teddy who is around 14 lbs is a constant barker. Even though I have been able to train all my dogs to do what is needed he would not learn.
I tried the can, clicker, citronilla spray, water bottle spray - nothing worked.
He is just over two and had worn a bark collar (shocking kind) for most of his life. I let the batteries die out over a year ago but if I take the collar off he will bark 24/7. With it on he is fine. Go figure?
He uses the collar as a reminder at this point as it would not do anything if he barked. It is just a reminder I guess. He also loves his collar and gives me sad eyes when I take it off.