You could try introducing him to the others with supervision. They will have to establish the pecking order and he will probably be on the bottom but it would be like raising a bantam with a flock of standards. He should catch up eventually just make sure he's warm enough outside.
You can put...
I would not let him have a lot of room to move and make sure food and water are close. Also keep him by himself for a while longer. Right now I think you just have to let him heal.