Ducks can make miraculous recovery, with good help.
Since a vet is out of the question, I will share a few things.
First - fix the security problem. Any who were not injured are still at risk. Please try to think in terms of what you can do, rather than what you cannot do on this.
The wounds need to be cleaned, and the feathers around them clipped back at least half an inch, so that you ca see what you are dealing with. Sometimes broken bones just need to be rested to heal. Sometimes they need to be set.
This site has some information that may be helpful with leg injuries - you may need to make a sling or slings to let the legs rest and the bones knit.
https://sites.google.com/a/poultrypedia.com/poultrypedia/poultry-podiatry
I will post more in a few minutes.
Some people medicine is fine for ducks - triple antibiotic ointment without painkiller, for example, as well as Epsom salt and many others.
The basic care ideas are to clean the duck or chicken, locate the wounds, clip and clean them, rinse with antimicrobial liquid like saline solution or Vetericyn, keep away from flies - repeat - keep the flies away they will lay eggs in the wound and complicate treatment and recovery.
In addition, electrolytes and vitamins in the water twice the first week or two, then once a week till they're healed - they need all the nutrition they can get to heal.
You may need to use oral antibiotics if the puncture wounds introduce bacteria to the bloodstream. It is important to try to prevent this by cleaning them up a.s.a.p. and continuing to rinse their wounds, and by boosting their immune system so that it can fight off infection.
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I would consider using Epsom salt compresses for some of the wounds - it is magnesium sulfate. It is also a laxative, so I do not recommend just putting it into their bathwater.