Hi I am not really very good with dogs not eating. I have always had multiple dogs at home so they eat no problem. I know a lot of people have great sucess with the BARF diet.
Only input I can give is years ago, I had a rescue Shih Tzu, when I got her at first she would not eat. I used to mix chicken gravy granules into her dry food and that worked, although probably not good for her at the time due to salt content etc...But I felt the bad outweighed the good in that situation until she settled, then she was okay with food