He is in a tub already, humidity isn't a massive issue. The thing that bugs me a little is the fact that he keeps getting moderately sized pieces of mulch stuck in his mouth. I'm sure any smaller pieces will pass but I don't want any pieces stuck in his mouth for too long and I don't want to stress him out by having to remove them :-/. I do not leave him unattended during feedings, I watch him (assuming he will let me) and I make sure that nothing serious goes on, but it worries me just a little bit... And because I feed f/t during his feedings sometimes they will get mulch stuck on them because the mice are slightly damp.