You are wise to be concerned. It is not good for turtles to eat too much bedding, even if it is digestible. Luckily, this is an easy fix.

Feed the turtle in a separate tub that is lined with wet paper towel. This will also insure there is no food in the bedding-that means less mold and the turtle will likely defecate on the wet paper towel as well-less clean up
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Tess Cook
www.boxturtlesite.info