I have a 10 week old silkie chick that was injured by a larger chick.  She was exhibiting neurologic symptoms so I brought her in the house for recuperation.  Since she wasn't physically injured, once she was stable, I would put her out in our small enclosed backyard that I use for a chick grow out pen.  The come in at night.  During this hospitalization, Wiggles would play with her new buddies, two 7 week old polish chicks.  They became great friends.  When it was time to go back to the coop, Wiggles was immediately accepted back in by her silkie buddies.  However, she found her way back into the small yard with the polish the next day.  I looked everywhere to figure out where she managed to get in...the big chickens yard and the grow out yard share a fence..I didn't want the big guys to get in to the babies.  I still have not managed to figure out how she gets in but this is day 5 and she still continues to spend her evenings and nights with the big chickens and her days with her polish friends!  
I was really worried about her ability to cope since she exhibited signs of a brain injury..but, even with a slight head wiggle (thus the name) she managed to figure out how to get to her buddies!  Now I'm not so worried about her living a normal life!