
Just a thought - don't know if this has already been mentioned. Does the pup get much exercise? I too have a tiny flat nosed dog, simiilar weight, similar eating problems! Only thing that seemed to have any effect on her appetite was taking her out for a good run every day. Has been eating pretty well on JWB wet pouches + kibble with a little melted butter poured over. But in the past week with all the snow, she hasn't been going out for her exercise, and her appetite has dramatically decreased. She now regularly turns her nose up at the JWB - I take it up and offer it again later but she's still only eating about a spoonful. Hopefully this will improve once the snow has thawed!
Don't lose heart - I've been exactly where you are, and I know it's very upsetting and frustrating.