Under weight

Question
Hello,
I have 2 staffordshire bull terriers one 18 months and one 9 months the 9 month is ok and keeps weight well, but the 18month old looks so skinny sometimes even after he has eaten he looks like he has never been feed we have tried increasing his food but it gives him bad wind, I don't know what else to try with him its so frustrating because he has a lovely coat and such a nice nature but he is just so skinny???Thank you

Answer
There are many factors to this problem. One of them is worming, intact or neutered, protein-losing enteropathy, etc.

A full work up should be done by the vet. In the light of a clean bill of health, then you need to look at the diet and the needs of this dog.
Let me know what kind of food you are feeding and I can give you a better recommendation.