This man doesn't care much for his dog. He knows his dog caused trouble, and he doesn't want any more trouble. Yes, it was the right thing for him to do to come face you, and I applaud you for making it easier on him and not making him reimburse you for $250.
However....... I have my own feelings about a lot of this after having lived on a farm, dealt with stray dogs, feral dogs, numerous varmintsand my own beloved pets. We have a long, complex history of having to deal with situations involving dogs.(I guess my signature says a little bit about it....)
Here's my 2 cents worth. DO NOT feed that dog if she comes back. Call the owner to come get her, or if she is attacking your livestock, shoot her. Forget the pellet gun. Forget the ball bat or shovel. That is not safe against a dog that is set on attacking you. You have lost your advantage when you get close enough to hit her with a bat. Shoot her quick and humanely. If the first shot isn't good, finish her quickly. Sound hard hearted? I think not. I have a number of dogs, and some dogs simply cannot overcome their instincts to kill birds or other animals. I have one like that. In spite of shock collars and various other means of trying to stop him he is simply obsessed with it when he sees the chickens. He simply cannot be trusted around the chickens. None of the other dogs bother them at all. If this dog had such a good time killing and maiming your flock, I would be willing to bet she would do it again, given the chance.
Get you a good 22 rifle, preferably one that you can do a quick follow up shot if necessary, not a single shot rifle. I prefer a lever action, such as a Marlin 39A. Hopefully you WON'T need it for this dog, but if you have chickens, it works pretty good for raccoons, foxes, etc. If you have to dispatch the dog, be sure to let any officers know the dog was killing your chickens. You tried to stop it and it came after you. End of story. It doesn't hurt to let them know you were sure sorry to have to do it, that you are really fond of animals and dogs. Of course, keep your cool and don't loose control in anger if you have lost more of your flock.
I am sorry you have had to go through this. I am sure this has been really stressful for you. You do have my sympathy. I hope you can prepare yourself in the event of something like this happening again (Heaven forbid).