I don't mean to steal your thunder here. But I worry about the same thing with my boy. He's a year and half, has longer legs, and weights 3.6 pounds. He is also neutered already He looks on the thin side and the vet says he is a tad bit underweight. I currently have both of my boys on Taste of the Wild but I don't know if I like it anymore, for reasons other than what is being discussed. I have been trying to order Blue Buffalo Wilderness because it is higher in calories and he is an active dog. Well I have been trying to order it for the last month and it is getting put on back order. And I have tried wet food but it gives his the runs. Is there anything else I can do?
And I would wait til after she is spayed. Animals tend to gain after they are fixed. Good luck with the spay!