I went back over the things you've said about Hank. In one breath, you said high value items are given separately and in another, Hank attacked Haley for a bone.
Bones are a high value resource in our house, they are much coveted. When we give our dogs bones, they are crated. When each dog finishes, I release the dog from the crate and remove the bone.
I have very nice dogs, no aggression issues, but I know if a couple of them wanted another dogs bone, he/she would not hesitate to try to take the bone away from the other dog and a fight would ensue-no question. I don't see this as aggression, but an aggressive act when there is fighting over a resource.
Meals are a different story, they happen like clockwork at 6 AM & 6 PM daily. They don't consider them high value and we've taught them they are not to touch each others bowls when they are finished. They are fed all together in the kitchen.
Lets take that attack off the table for now. We are left with the dog park issue, unless there are more problems that you haven't mentioned?
I don't know about your dog park, but our local park is an accident waiting to happen. On any given evening, there could be up to 50 dogs at a time, chasing after balls, running into one another and people. It is utter chaos and enough to send a hyper dog over the edge. I'm not making excuses for Hank, but it certainly can heighten emotions (a hundred fold) for any dog that is the least bit excitable. I imagine that it could be a highly stressful situation for Hank, even though you thought you were doing a good thing for him.
It is easy to say I think it's the pred., so there's nothing I can do about it. It is much more difficult and time consuming to try and work through this, but I'm sure you believe Hank is worth it. I would agree that Hanks aggression *can* have an impact on your puppy, and then you will have two dogs with issues instead of one. So, SOMETHING has to be done.
I understand you have money issues, there's no shame in that. Who doesn't these days? Maybe you can't afford a behaviorist right now, an initial consultation is around $200, give or take and they usually last 3 hours. Then they make recommendations based on information & observation. Above all else, consulting a behaviorist can give you some peace of mind.
If you can't afford it right now (but I believe it's the best way to go) find a class/trainer that will take dogs with aggression issues, one on one is even better and around here, you can get a knowledgeable trainer that will work with you for $30 an hour.
When he attacks I use a stern deep voice and say no and get in there and pull him off of the other dog and and then put him on his back and hold there and growl at him till he relaxs his body and calms down.
That isn't the best way to handle the situation. Stern voice, yes. Pull him off the dog, yes. Snap on his leash and remove him from the park immediately.
There's no reason to put him on his back to make him calm down. Just removing him from the park will do that. You don't want to create a situation in which he fears you, either. You could be teaching him to fear humans and direct his aggression toward people, too. Even if the pred is at the heart of the matter, learning how to modify his behavior will make you more confident in sticky situations (always on lead for Hank from now on). I have a lot of very good materials on training and working with aggressive dogs. If you email me, I will send them to you.
Garden_girl@Graffiti.net Could be helpful so that you know what to look for in a trainer.