Undigested feeders is usually the sign of parasites, in proper heating temps, or in proper supplementation. Though there are probably other causes these are the most common ones I have seen.
I would double check your enclosure temps. My first female pooped out an undigested wax worm after she laid. I fed her one straight after then she went to sleep as it was night time. As she had been in her laying bin all day she hadn't warmed up enough to digest, hence it passing through undigested. That smelled pretty bad too. Food passed through normally again once she started basking again the following day.