Let us know when you hear back from the rescue. I know the feeling. the bad thing is, you don't know what kind of mange she has. Of course, it could also be severe flea bit dermatitis. Her ears may be fly bitten, resulting in a crusty bloody mess.
Sad. Just sad. People like that should be forced to live the same way they make their dogs live.
Here's an article I wrote on chaining up dogs?
910pets - Barking Up the Right Tree archive
We are trying to get this made illegal in my county here in NC.