Chihuahua ears

Question
I am a foster mom for a small breed rescue, and have recently obtained a foster chihuahua.  This is a purebred, almost 2-year old, 6.25 lb intact male.  He has a vet appointment this week.. but a question is burning in my mind and I'm having a hard time waiting for an answer!  His ears are peeling on the back - and I have never in my life seen anything like it.  He is not in pain... but there are literally hunks of skin/hair that look like they have fallen off.  Also, the tips of his ears look "burned", as in charred.  The skin is darkened and ragged.  (I know he was not burned - the surrender was from an acquaintance).  I am not familiar with the chihuahua breed and was wondering if this is common? Like I said he will be completely vetted this week - and I'm sure we'll know something then.  I'm just curious.  

Also of note, the surrending family kept this poor boy crated for the majority of a 24-hour period.  Could these be rubbed off spots from the crate?  He looks like he has some thinning hair on the tops of his paws also... but nowhere else.  

The former owners fed him "Dad's" kibble.  I've only had him since Saturday.

Answer
Actually sounds like he had ear mites or fleas, The ragged peeling skin is probably from repeated scratching with toenails that needed cut. Eventually the hair doesn't come back and the skin develops a dark, leathery texture. The thinning hair on his paws could be from constant licking, or poor nutrition. Bless his little heart. And your BIG one for helping him. Put a little oil in his ears and rub some on the backs of his ears as well. It'll ease the annoying itch hopefully. A GOOD bath is foremost, but I'm betting you've already done that.blessings,
Cindi