Yes - maybe find one hen to put with her, just as @1muttsfan suggested. If that doesn't work, you might consider rehoming her.
I made the same mistake. I gave my broody 1 chick. My broody raised that chick, but she has struggled. She's still bottom of the pecking order and a little neurotic. She was never injured, though. I will NEVER add only 1 ever again.
I made the same mistake. I gave my broody 1 chick. My broody raised that chick, but she has struggled. She's still bottom of the pecking order and a little neurotic. She was never injured, though. I will NEVER add only 1 ever again.