Re-Introducing chick to flock

[Lisac45]

i purchased 16 chicks about 2 months ago. One of them got sick after about a month, we had a cold front come through for a few days.
My vet figured it was a respiratory infection so I brought it inside and treated it for 10 days. Then it was another week before I could get a place ready for it in the coop. He, I think, is in a look don’t touch cage and has been for a week. I would lime to let him out a bit but I’m concerned because he is smaller than the others and I feel like they will swarm him.
Any advice?

 

[aart]

So they are all 8 weeks old?
Have they been bugging him in the crate in the coop for the least week?
I'd give it a try letting him out, see what happens while you supervise.
Knowing more about your coop and run would help,
dimensions and some pics.