If you don't know the story of Donkeyskin go on Wikipedia

I think the original story is far too risky for Disney's standards - there's just too much content that I don't think the company would allow in a movie of their own. But then again, some other fairytales have questionable content too and so Disney just changes them a lot until the story is acceptable and family-friendly enough.

I think a movie based on Donkeyskin would need to be very loosely based on it. A lot of the plot would need altering, but it could serve as a basis for a story at least.

Yes but they'd have to change some of it