It sounds like you rescued this dog from a bad situation and she is lucky to have your home as her home. Why would a dog be running loose at the fair if it's home was a good one? Do your part by putting the local shelter on notice, but if you love the dog and can keep it, I agree with Rachel, KEEP THE DOG!! When I found a puppy several months ago, I utilized the local paper and ran an ad for 7 days. They gave me three lines free of charge. Not one person called. If someone is really missing their dog, they would look in the lost/found section of the paper and call the pound or local shelter.