Did my chick imprint on me and what can i do?

[Naya]

Ive posted about this chick before, he was sick and had to be separatet from his siblings for a quite long time, because everytime we tried to reintroduce him to the group, hes physical state declined rapidly.

Hes much better now, almost as big as his smallest sibling and very active and strong. Hes on antibiotics atm (our vet said he either has a "superinfection" or his immunesystem is too weak to be around others, in which case we probably need to put him down) and technically ready to go back to the group, but now he doesnt even want that anymore.
Everytime we try to put him in their cage he jumps right out and comes running to us. And if he doesnt find a way to jump out, he avoids the other chicks or runs around pecking them, aiming on their eyes. It seems like he has no idea what to do around them or why hes even there. When hes in his own cage or on my shoulder/lap hes super relaxed, making the typical "happy chick" noises etc, but around others its the exact oppsite.
I dont think its fair to euthanise him because of this when hes finally happy n healthy, has anyone had a similar problem and how did you fix it? I cant have him separated forever :/

 

[TOMTE]

Start with short introductions. Put him in a dog crate inside the run or wherever you have your other chicks. Let them look at each other, talk to each other, do their chick things around each other, but they are not allowed to touch each other. Sure, he's probably not going to be happy at first, but he'll (hopefully) realize he belongs with other chickens before long.

Do this every day for a week or 2, extending the time they're around each other. Once they're all acting business as usual, you can try putting him in with the others, without the dog crate. Keep an eye on them for a while to watch what they do.

This isn't something you want to rush. If the others don't accept him, they could kill him. Chicks can be brutal. So keep it slow and steady.