Don't we just hate this kind of stuff?  This is what I think:  He feels helpless and put upon because he can't legally do anything about your roosters making noise.  He wants you to feel just as helpless so he made a threat (that he probably will never carry through).  He wants you to care about how he feels.   Don't expect help from law enforcement.    A prosecutor would never do anything about this; too hard to prove.   They will tell you its a civil matter, take him to civil court.  So, the next move is yours - or not.
You can do something or do nothing.  If you do nothing, the two of you will be even in his eyes; your roosters are bothering him and he has threatened (bothered) you.  If he does actually shoot toward your house, he is an idiot and you will want to take action and the law will get involved.  If you want to hinder him from the possibility of shooting at you, you might consider a taller, denser fence that he can't easily see (or hear) through.  
All that said, this is what I'd probably do:  First, switch your thinking from getting even to getting along.  Take a dozen eggs and knock on his door.  If a member of his family answers the door, ask for him.  When he comes, tell  him you are sorry that he was so upset.  Tell him that you never intended for your pets (call them pets) to bother him or anyone else.  Tell him what you are going to do about freezer camp or anything else that is true and hand him the eggs.  Whatever happens, you take the high road.  Don't appologize for your chickens, don't mention his threat to you, just SHOW HIM THAT YOU CARE ABOUT HOW HE FEELS.  Period.  That's really what he wants.  
Many here will disagree with this approach.  You can take what ever approach you choose.  But if your goal is to end the conflict, this is what I would do.