Sorry about your chicken Karri and can sympathize on the migraine. Like Katy, my migraines were stopped some time ago, cured by my hysterectomy I believe.
The thing is, I know about small town living and all, but this dog has growled at a child. If that happens again (the growling at the child, not the chickens I mean), don't call animal control; call the police (one of the few times I would advocate involving police in a neighborhood problem). That's a life threatening situation. If the owner is coming on your property w/o invitation, that's trespassing as well. Unless the cops are real jerks, and that type exists, they are going to be concerned about your child's safety, not how many chickens you have.
Katy, we too have problems with people "rehoming" their dogs by dumping em on us out here in the country. The subhumans I hate the worse are the ones that dump em, but leave the collar on. If the animal is lucky and can sustain themselves on food, they slowly die anyhow from choking on their collar. I had my ex put a dumped dog down for that very reason. And me, the pacifist. and that's all I will say on that subject.