A bit of banana makes Chase poop...and walking seems to help him work it out too. Though he has never been constipated more than 24 hrs. so I'm thinking those may not be feasible solutions for you. I have also heard the pureed pumpkin works too. Good luck!
Chase (Friendly Resident Wigglebum) - Border Collie/Lab/Shepherd X
Kailey (Misunderstood Gentle Beauty) - GSD & foster failure #1
Rupert (Gold-Medal Winner of the 3 a.m. Kitty Destruction Olympics
Heidi - RIP my sweet baby girl