Why the gas? I ask that same question about myself.

Seriously, dogs are like people and who knows what it is that they eat that gives them gas. I had two dogs with terrible gas and loose stools and once I took them completely off of grains, both issues resolved almost immediately. Their constant feet licking and tear staining disappeared as well.
Wellness Puppy looks like a good quality food but it does contain sweet potatoes and fruit which can make dogs gassy. Too much fruit can also cause diarrhea as can allergies to any number of things in dog food. I was lucky to discover rather quickly that my dogs don't tolerate grains. I hope you are as lucky to quickly find whatever it is affecting your baby.