I've been on a tour of aussie and when i came back my Yorkie boy who is 3 (and been staying with my parents) has two large black patches of hair of his lower back! they assumed he was once again changing coat colour.
My Yorkie girl has also been there along with their chihuahua and none of them have any skin conditions or fleas (we don't do fleas

)?!?
Totally confused the hair is very healthy and soft but is short black with a few red strands.
Any help i am completely confussled