The high quality less fillers makes them poop less, but I also give my dog sweet potato chews which helps move things along if you will. It is less messy than canned pumpkin and my dog enjoys chewing on it. I only give her one a day and it has not made her have runny stools or anything like that, just keeps her regular. There are several out there that I have tried but my fave are some that I first picked up from the vet and now buy online (Bichon Fries) at
Pet Boutique - Dog Pet Store Supply