My Dog has recently started farting, a lot.?

I have a 1 yr old female American Staffordshire Terrier. I feed her California Natural (Herring & Sweet Potatoe). She has been on the food for quite sometime and never ped gas before. At least not like this. Within the last month she has started ping gas constantly. Also I notice her appetite has increased recently. ANY ADVICE OUT THERE. Dog Beeno maybe? Help.