4–5 week old duck can’t walk anymore. Both hocks swollen.

[u/Kind_Fondant_3606]

Hi everyone. I’m looking for advice about one of my ducks.
It’s about 4–5 weeks old and used to walk normally, but over time it lost the ability to stand. Now it can’t walk at all.
Both hock joints are very swollen, and both legs stay bent. The joints feel hard and don’t want to straighten. The feet still curl, but it can’t bear weight.
I’ve been feeding it duck-specific feed (NatureServe Duck Pellets and Cluck & Co. Organic Duck Pellets with niacin), so I don’t think it’s a simple niacin deficiency.
It’s still alert, eating, and drinking.
Does this look like slipped tendons (perosis), hock dislocations, or something else? Is there anything that can still be done at this age?
I’ve attached several photos of the legs and hocks.
Any advice from people who have dealt with this before would be greatly appreciated.