"The name denoted strength and power, and it tied in to the city's meatpacking tradition and the Chicago Amphitheater's (first home court of the Bulls) proximity to the famed Chicago Stockyards. The one-syllable directness of the Bulls was also in line with Chicago's other team nicknames-Bears, (White) Sox, Cubs, and (Black) Hawks." The above is from the official NBA website. http://www.nba.com/bulls/news/behind_the_name.html
No they didn't change their name. They are still called the Chicago Bulls.
The Chicago Lions
The name comes from the great stockyards in that were once located in Chicago.
Up until the 1970s, the city of Chicago had what was called "the stockyards". These were slaughter houses, located on the south side of town, where cattle were brought in by railroad, slaughtered, and send out by railroad to be sold as beef products. With this history, it's understandable why the city's basketball team would choose to name their team players after the male cattle, bulls.
Chicago Bulls
Benny the Bull
Chicago Bulls
The Chicago Bulls.
His name is still Scott Williams
Chicago Bulls Washington Wizards
Chicago bulls and the Washington wizards