Guinea Pig Changes

Question
Hi, Cindy, thanks for your time.  I noticed that my guinea pig's feces the last two days has been very dark and has a distinct new odor--kind of a strong sour smell you detect when you walk in the room.  They are still in pellet form, however, and he is otherwise completely healthy.  Wasn't sure if I should start seeking out an exotic animal hospital or if you've ever seen this before.  Thanks!

Answer
Have you made any changes in bedding or food?  What veggies are you giving him?  Just like a human's fecal material changes according to diet it could be the fresh fruit or veggies.  Also, have you started giving a vitamin complex in his water.  That too could have an effect.  These are my intuition and I wouldn't go to the vet unless he starts to lose weight and acts sickly.  Good Luck, Cindy