sick bird
That looks like a fancy bird to me !!! Those scab looking things do strange they could be a result of injury but I reckon they could be mite !!! Hopefully you will be able to catch her and find out where she comes from. If you can't catch her all you can do is put food and water out for her and see if she heads off when she feels better.
Thanks for taking an interest in her Biggles, all the best.
Thanks for taking an interest in her Biggles, all the best.