My frenchie puppy has been having mostly soft stool for the whole time we have had him. He is 5 months old. We have had two rounds or antibiotics and tested negative for giardia and parasites. His good is a chicken and brown rice Nutro brand puppy kibble. The vet suggested to put him on a special gasto intestinal kibble for couple weeks and probiotics. Any suggestions? His energy and appetite are totally normal!