When I went to give my piggies veggies and clean up this morning, I noticed a white discharge from one of my piggies that was on the fleece. It was even on his poop as well. I've never seen this kind of white discharge before, let alone seeing it on his poop too. I don't think this is just regular pee drying up, as I've never seen this in their half a year of living in this cage. Is this any cause for concern? Any help would be greatly appreciated.
Here is a pic where you can see the discharge on the fleece and poop: