Firstly, your dog is 12 months old. She is only a puppy, so while she has "obedience issues", not returning when called and chewing things are what pups do.
Some people have assumed that your dog has ripped these animals to shreds. Is this the case, or has she accidently killed by a crushing bite (puppies do bite too hard during play) or playing with for to long until stress and exhaustion kills the animal?
By your words, your pup is a "useless bloody pig dog". A dog that has been bred for an extremely high hunt drive. When a small animal runs, it may just be instinct kicking in to chase and retrieve/rip to shreds.
In my line of work using detector dogs, a dog with no hunt drive is failed very quickly. While our dogs are fine around people (and they are never associated with any other animals) to do chase whenever they see wild bunnies. I'm sure they would think the bunny would be a play reward if they ever caught one.
Are you going to be using this dog for pigging? If so, you wouldn't want your dog around any other animals, if not, I would start training her now while she is young and eager to learn.
You aren't keen to take her to the dog club as she gets excited. This is the behaviour that you want to correct and there are people there to help. (Never dealt with any, and it doesn't sound like Bark Busters have a good rep. "Bah" What's that suppose to do?) You also need the training to be able train you dog. You
will need the alpha position (you need to be the dominant figure, doesn't mean you need to dominate the dog) I your dog thisks she is alpha, why would she listen to you, the sub dominant animal?
I could go on forever, but there are so many didn'tthings you can do to train your dog. Many won't work, but that doesn't mean nothing will. Try one thing, then another until something shows an improvement. You may need a combination of a few or many things.
For now, I wouldn't feed her anymore live guinea pigs.