Well, I guess it's okay if your cat's litterbox habits and bowl movements remain the same. My concern would be with the roughness of the edges of the popped corn on your cat's intestines.
I had a an episode a while back with my one of my cats (Bear): bloody diarrhea. Yikes! Turned out it was the kibble and Bear's "senstive stomach." Bear is fine now that I changed his food and revised his wet/dry feedings.
Vet said cat's intestines have blood vessels close to the membranes and therefore can sometimes easily be ruptured with rough feed, so bloody stools are not always a dangerous sign. (I was thinking in human terms, blood-stool-colon cancer...but it doesn't work that way with cats).
So, popcorn-feeder, just be aware of possibilities
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