A national animal rights advocacy group is speaking out against "Chicken Challenge" games being played at Aztar Corp. casinos, including Evansville's Casino Aztar. The game, which features a hen playing a human in a game of tick-tack-toe, made its debut June 1 at Casino Aztar. The hen is inside a game machine and places her "O" on the tick-tack-toe board by pecking on a screen. Humans who defeat the highly trained hen win $5,000. People for the Ethical Treatment of Animals wrote a letter Monday to Aztar Corp. President and Chief Financial Officer Robert M. Haddock alleging that the "Chicken...