FOR LARGER DOGS:
We so sorry you are going through this. CHR only takes in dogs under 25 pounds. We know the challenges that come with caring for dogs with problem behaviors, particularly dogs that bite. We have had great success in our own rescue improving the behavior of fear-aggressive dogs, so we know that training can work. However, it can take up to a year of continuous training to reverse the biting behavior, which is not feasible for many dog owners. It sounds like you have tried a range of things to help your dog, so we understand how difficult this must be for you.
There are many rescues listed on Petfinder.com that focus on medium-to-large dogs. Please continue reaching out to multiple rescues because you never know who may respond.