I had the same problem with my beagle a few years back. We tired the more exercise and every dog food under the sun. Finally I just stoped giving him other food expect for dog food. First day he didn't want anything to do with it. Second day he nibbled a little at the dog food, third day he nibbled some more. After a few days he learned he will not get anything else but his dog food and he started eatting it. The last thing you want to do is feed the dog off your plate. The dog will come back everytime you have a plate. He will also go back to the person thats feed them off there plate. Recently I had my grandmother living with me and she would feed the dogs of her plate. Everytime she would sit down with a plate of food they would sit around her waiting for there piece. She would always give them a small piece. Now that she has moved out the dogs don't even come around the table when we eat. They know that we will not give them a piece. If they get anything we put it in there food bowl.
That doesn't necessarily matter. My dog (a tiny chihuahua dachshund mix) was the same way. He would eat a certain food for a little while then would just stop. I'd switch his food, and he would do the same thing. Whether it was wet or dry. I take him for quite the long walk for his size everyday and still, he would just not want to eat his food. There might be an underlying issue with what is in the food, something she may be allergic to. Which is the issue with my dog. After having the expensive allergy testing done i found out he had quite the many food allergies. Currently i am making him his own food until i find a suitable dry food for him. But my suggestion is to talk to the vet about it. Does she show signs of allergies? Scratching often, puffy watery eyes, rubbing her face on the floor?
Dogs who don't enjoy their food usually have issues beyond the food. Most need exercise, exercise, and more exercise! Dogs were not meant to be couch potatoes, no matter how large or small they are. If your dog is getting enough exercise, believe me, she'll eat what is put before her.