limping duck

I have a 3 mo. old duck that was attacked by my dog about 2 1/2 weeks ago. She was ruffed-up & her feathers pulled, but no bite marks or puncture wounds on her. Then last week she started to limp. I looked at her foot and the toes are swollen and curved. Is thisan injury from the dog attack or could this be bubblefoot? My ducks are free-range all day and put away at night. Their bedding is dry and clean. What do you think??? How should I treat this??