Indian runners are susceptible to leg injuries as are all breeds of duck. Indian runners tend to be a timid breed.
Access to bird houses need to have plenty of grip if the house is off the ground and a ramp of any sort is in use, to prevent slipping and injury.
It is reasonably rare in runner ducks but does happen. The sinus can become blocked causing a swollen cheek. A course of antibiotics can help but not always. Some vets suggest aspirating the sinus and a course of antibiotics. However, some ducks are just susceptible to this problem and have to live with it recurring. As long as there is always a fresh supply of clean water for them to clean their bill in it can be controlled and minimised. This information is only based upon my own experience of keeping ducks and advice i have been given by others, if you know otherwise i would be grateful if you would let me know. Call ducks are most susceptible to blocked sinuses as their bill is alot shorter.
Sometimes birds can develop a condition called angel wing, this is when the wing constantly hangs down and sticks out at an angle. Some thinkers on this condition consider it to be a genetic abnormality exacerbated by inappropriate diet during development ie too much protein in the diet. However, during wing development the wings may hang down as they become engorged with blood at different stages of growth, mimicking angel wing but this infact just rights itself as the bird strengthens.
If the bird does have angel wing experienced bird keepers suggest taping the wing up for about 4 or 5 days, if after this time there is no improvement try taping again for a further week. After this time if no improvement the bird will have to live with it and will never fly.