Complex sentence: The production began at Chuck Jones'MGM Animation Studio in the late 1960's after finishing on The Phantom Tollbooth and another Dr.Seuss special, Horton Hears a Who! but then MGM stopped production and closed down the animation business for good in 1970.
Split into simpler sentences: The production began at Chuck Jones'MGM Animation Studio in the late 1960's after finishing on The Phantom Tollbooth and another Dr.Seuss special, Horton Hears a Who! But then MGM stopped production and closed down the animation business for good in 1970.