How old is your pup? He might just be a larger breed of yorkie. When my dog was a pup, he barely weighes 2 lbs for the longest time! He's 1.5 years now and is barely 4.5 lbs (I weighed him yesterday), no matter how much I try to make him gain weight!
Oh, and I think the chicken soup is a good food (look for reviews on here), just make sure you're giving him the right ammount. |