I noticed that my foster rat's throat and upper torso is quite wet, and that his mouth and forelegs seem to be stained with a bit of red. I don't know if it's blood or just porphyrin. The moisture on the underside of his throat didn't smell like urine, and it was clear. He seems to have been a bit less active and hasn't been eating as much today, but when I gave him some yogurt he ate it quite happily.
Any ideas?
Any ideas?