i am sorry i didn't see this sooner. once the hock joint is damaged it is very hard to treat. i just lost a chick that i tried to treat for this after 11 days of splinting, she had both tendons slipped but i caught it in less than 24 hours. i learned a lot about what to do and not to do. this site has some helpful info http://www.peafowl.org/ARTICLES/1/
you need to splint it in the correct position that the chick would normally stand in and maybe make it a chick chair to rest the joint. how old is your chick? can you post a pic? you can pm me if you want more info and i will try to find some of the other sites i used for mine.
Can you get a pic ???? I had one that would hold his leg up (i think it might be the same as your talking about) When we tryed to pull it down it would just go back up, hubby and I tryed splinting it straight, when we took the splint off the leg was straight but also out to the side a little (from the splint) He made it a little while but as he got bigger had to be put down b/c he couldn't handle the weight !!!!! Hopefully you can post a pic of him so I can see if its the same thing.
don't feel bad. it happened to mine as she was kicking out of the shell. i tried everything to make it right but her bones twisted too and it was no quality of life for her. one is easier to fix than 2. just make sure the chick is on a very soft surface so the hock isn't further damaged until you can splint.
the easiest way to put the tendon back in, according to the poultry orthopedist, is to straighten the leg to the back and gently pinch with your fingers to roll the tendon back to the middle. you can tell if it is out because the hock will look flat in the back when their leg is bent. if the hock is swollen then it probably won't stay in the first time and may need splinted for a few days to let the swelling go down. a chick chair is easy to make and keeps the chick from aggravating the injury. i used pipe cleaners and medical tape to make the splint, wrapping the tape back over itself so it was not sticking to the chicks leg and then wrapping around the leg. also vitamins in the water may help speed recovery.