Ok so I had a friend look after my guinea pigs when I was taken into hospital. Ok so there cage was a mess and they really needed a wash. When i was washing them i noticed one of them had black flecks over there fur I check it against toilet paper and there was no change. So the next day I was brushing her and noticed all these flakey brown parts in her hair. What could it be? I have dog but she is totally flea free. I bathe my guinea's in gorgeous guinea pig shampoo for long hair, I have changed there bedding and the other one is fine. Any ideas