hi. does anyone know what could be the cause of my guinea pig suddenly starting to excessively shed? she's always shed a bit but for a few days i've noticed huge patches of hair on the floor where she lays and today I lightly tugged at some of her back hair and it came out with little to no force. i do not think there are bald spots, though. she is on revolution and has been for possible mites so i am not sure why this is happening. could this be related to stress (we just lost her cagemate)? thank you.