I'm not very good at explaining that sort of thing and those were just pictures I found on the web. Do a search for chick or chicken chair or chick or chicken sling.
-Kathy
If the hock is swollen, it's almost certainly slipped tendon. The problem is that once the hock become too swollen the tendon will not "snap" back into place, but either way, one should be able to very clearly feel if it's not in the center of the hock.
The pictures below are to help you...
Welcome to BYC!
Here is a link you might find useful:
https://sites.google.com/a/poultrypedia.com/poultrypedia/poultry-podiatry
I've treated a few with slipped tendon, and the only time I did it successfully was when I put the chick in a sling for a few days. You could try to make something...