oh yes, smashing kibble - been there
When TJ was having the mucus poops, we first tried the food allergy test. I switched him to a Duck and Potato flavor - Natural Balance also carries it. Unfortunately, it didn't stop and we went to the blood testing, and that's where we found that TJ's folate levels were sky high, without doing a biopsy, the Vet could venture to guess he had an overgrowth of bacteria in his small intestines, IBD - we tried the metrodolize (sp - I have no idea

) and it didn't help either, that's when we tried the Tylan powder, and that's what helped TJ. He had to be on it for a year, but now he's good as new.
I am hoping for your little fella that the change in food will indeed stop these poop episodes...oh and the noise that would come from TJ, I swear these was a monster in there...poor baby...
Keep us posted, give the new food a try, but if it continues, I would suggest doing a blood panel to see if anything is off