Duckling I took in has niacin deficiency issues and a growth near its tail

[EronicaV]

2 days ago I took a single duckling in from someone who had several ducklings and all but one died.
I don’t know how they were cared for or how long this duckling spent alone. I know they were gotten at Easter time so it should be about 3 weeks old.
Yesterday, I got a 1 week old saxony duckling from a local breeder so they the pekin wouldn’t be lonely growing up (we’ve got 3 adult ducks to put them with eventually).

The pekin duckling has problems walking and with balance and lays down a lot more than it should. Legs are wide set, thick hock joints, feet overlap a lot, and it has a small growth about where the oil gland is. I already put them on unmedicated chick feed with 1 tbsp nutritional yeast per 1 cup feed to supplement niacin. The pekin duckling does eat and plays in the water when I get out their “pool”.

What else can I do for this duckling?

Is there a better way to supplement niacin?

I attached images of the growth although it’s hard to capture, any ideas of what it is?

So far, there hasn’t been bullying between the two differently sized ducklings, but should I be worried about the smaller one?

thank you for any replies!

 

[KaleIAm]

The location of the "growth" in your photo is where ducks have a preen gland. They rub it with their bills to get an oil/wax substance and then rub that all over their bodies to become waterproof. It is like a little nub covered with downy feathers that gets oily. Your duckling's is likely immature at this point.

Sorry I'm not sure about the leg issues. I haven't had much experience in that area.

 

[EronicaV]

The location of the "growth" in your photo is where ducks have a preen gland. They rub it with their bills to get an oil/wax substance and then rub that all over their bodies to become waterproof. It is like a little nub covered with downy feathers that gets oily. Your duckling's is likely immature at this point.

Sorry I'm not sure about the leg issues. I haven't had much experience in that area.

Okay thank you! I didn’t realize their preen gland could be raised up like that, or maybe I just never noticed it with any of my other ducklings. I’m so glad it’s not an issue

 

[KaleIAm]

Okay thank you! I didn’t realize their preen gland could be raised up like that, or maybe I just never noticed it with any of my other ducklings. I’m so glad it’s not an issue

I can't say 100% confidently that it is a preen gland just from the photo, but it does look to be in the right spot. Here is my duck's. Photos are really hard to tell how high it sticks up.