Introducing fawn to adults

Hi- I'm new here. I'm mostly raising deer for pets. I have 3 adult deer (a mother and her doe (yearling) and buck {2 years old}) and I have her buck fawn (3 weeks old) and I'm getting 2 unrelated doe fawns (2 days old). Currently the buck fawn is in my house (he is blind) and he is bottle fed but I would like to put him outside.
My Question- at what age can I put bottle fed fawns in with adult deer?

Blind fawn

We did not give B-12 or thiamine... I had vet look at him and he said those things wouldn't help- he was just born blind. He's a piebald- that might have something to do with it.