It could be a vitamin deficiency. I have a bantam oegb or d'anvers (not sure which) that developed curled toes and inability to walk at three weeks old. The only thing I've found that seems to fit is a b-vitamin deficiency. Since you're feeding home food and not a complete ration, that could be the issue.
I started giving poly-vi-sol without iron a couple drops a day, plus in the water. You could use a chick vitamin mix in the water. I tried a chick shoe and leg hobbles the first day and the poor thing couldn't move, so I took them off. But I was worried that it would develop incorrectly because it was sticking it's one leg out sideways/backward all the time, so I tried the hobbles and just one chick shoe on the more curled foot the second day and she is starting to move around a little bit now.
She is in a seperate part of the brooder from the others because I was concerned she would get trampled. I make sure she drinks several times a day, especially when she couldn't really move herself, and I put food down right in front of her so she can eat.
What I read said if you start giving vitamins when you notice it, it should get better in 3-4 days.
The leg hobbles I am using is a soft hair band twisted like a figure eight with the loop around each leg, then taped around the middle part. This seems to work better for her than the tape hobbles I tried first. The chick shoe is just two pieces of scotch tape with the toes uncurled in between. As a bantam, she's small enough that this works.
Search for the Poultry Podiatry page online for more info.
Good luck.