I Also have a duckling who has a slipped tendon, one of his legs is just tucked up and a little twisted, the vet could not twist it back so gave me anti inflammatory and pain killer and i was told lots of swimming, as it might just pop back. I don't want to try to do as I don't want to hurt my little baby. I also have a kharki cambel who i took in as a companion, (the disabled duck was one i hatched my self a rescue malard. I hatched a lone egg last year, that was my duck crispy, but he flew away when he was old enough. We live on a huge house boat so when he got to see all the other ducks he was off. !! anyway I now have a new addition called Aro (matic) and the kharki cambel, is two weeks older this is Pan (cake),
And when i took Aro out the incubator i realized his little leg was bend sort of up and outwards, i thought it was fused at the knee, but then i done some research and then to a vet and found it was a slipped tendon, other than that he is now 2 weeks old and managing fine. he hops about faster than the Pan lol

, he used his knee to pruen his little belly. and I keep an eye on him ( they cone in the boat at night and play and sleep by me in a big fluffy bed, and they are both now inseparable, and best buddies, I would not change this little on for the world, and what ever he/she needs, they will get it. if you do start up a disabled duck thread, please give me an invite I would love to update and see how al the other little ones get on.