pumpkin?
Have you tried the plain packed canned pumpkin? Not the pie filling, just plain pumpkin? A vet tech recommended it to me and it works! Only a couple of tablespoons though--and they do love it. Something about the fiber content. My boxer has the opposite problem, no poos, just constipated, but my springer spaniel girl has severe poops after she is stressed, as in a trip to the vet, being boarded, etc. Pumpkin works like a charm. Just make sure it is unsweetened.