CHICAGO, Illinois, Aug. 29 -- Shedd Aquarium issued the following news release: The newest and youngest penguin at Shedd Aquarium has reached a new milestone - independent socialization without its parents. The rockhopper chick that was hatched in June has been weaned and is becoming more independent. Now, the bird has begun spending time with other members of the colony behind the scenes, including one of the oldest penguins at Shedd and a local celebrity - Wellington - who also happens to be   more