She definitely needs to be seen by a vet! As for refusing food and choosing one...she is eating what you provide. If you only provide dog food she will eat it. After you take her to a vet to be sure she does not have something, I suggest you start giving her her dog food for 10-15 minutes and if she does not eat it, pick it up. Give her her dog food on schedule and do that same thing until she realizes that is the only food you are going to provide. She has you trained!
