How to use Commerce Feeds to Import Stock for the Commerce Stock module? I have the Commerce Stock module enabled for my products in Drupal Commerce.

But I cannot import data to the stock fields: When I set up the correct product processor, I can't see the Stock field which is present in my product variation type.
Your problem sounds similar to the issue: Not recognizing product variants fields.

The solution is most probably to upgrade the Commerce Feeds module to 7.x-1.x-dev, or if you don't want to use a dev version you could downgrade the Feeds module to 7.x-2.0-alpha9.