That looks like an infection to me. I suppose one could argue about scab or no scab. The duck needs antibiotics - oral - and a good long soak, in Epsom salt compress if possible or at least lukewarm water. Then apply a few drops of clear iodine to the bottom of the foot under the most swollen part. I would probably then apply triple antibiotic ointment without painkiller to the foot and leg three times daily and always right before bedtime. After five or six days I would check for a dark spot where the clear iodine was placed, and see if there is something that can be gently removed like the link I posted.
A good duck vet is best - I always try to remember to write that.
In any case, that looks infected to me. There may be a break, but the swelling looks like infection.
@Miss Lydia @casportpony any thoughts?