"Environmentalist Tom Steyer isn't happy that the conservative Koch brothers turned down his offer to debate climate change and the Keystone XL pipeline.

In an ad released Friday, the former hedge fund manager's action group NextGen Climate called Charles and David Koch 'chickens.'

The 15-second ad buy features two little chicks walking around, clucking with the words, 'We've been informed the Koch Brothers declined our invitation for a debate,' in bold letters across the screen."

Laura Barron-Lopez reports for The Hill May 23, 2014. [2]