it looks like she is favoring it but at least she is putting it down and trying. I don't think she has splay leg which would require hobbles. You mentioned the paint thing is there any place on it where she could have gotten her foot caught? or could she have gotten stepped on by one of your larger ducklings? You could try some warm Epsom salt wraps just put warm water and Epsom salt in a bowl and mix so the salt is blended into the water then take a soft cloth like a washcloth and soak it wring it out so it isn't dripping and wrap jer leg until the cloth starts to cool you can do this many times a day. Also, she needs along with the other 1 Tablespoon of Nutritional yeast for each cup of feed. At the age they are and her being Jumbo Pekin the Nutritional yeast is very important. I have 10 week old Runner females and each water changing they got liquid B complex in their water and nutritional yeast over every cup of feed they got.
Hopefully with rest and some extra niacin she'll be back up walking without pain.