If you think she has been injured your best bet would be to confine her for a while with limited room to do much but walk to feed and water. rest vitamins and water therapy are best for recouping. Vitamins B Complex 1 ml over a tasty treat daily.Water takes pressure off an injury which maybe why...
Yes def give it time. Can you give them a safe way in an out of the pool @onaharley put fencing around hers to keep the ducks from jumping out instead of using the ramp. Maybe she can share some pictures.
You can try doing it orally but probably best way is putting it over something she really likes like thawed peas or mealworms. Just enough that she gobbles down the whole dose. Please keep us updated on how she is doing. Give the others the brewers yeast if none are showing symptoms like this...
When a duckling is already showing symptoms of leg strength issues it’s best to get them on liquid B Complex it works faster, TSC carries it in the cattle dept 1 ml per day it will say injectable but we give it orally to our birds. Usually takes less than a week to see improvements .
You may have to go to a pet store and by fish antibiotics they will be same as what we use to purchase over the counter for our birds but Gov has taken that privilege away from us.