Viewership of children’s TV channels in the United States declined by another 20 per cent in the past year, according to Bernstein Research analyst Todd Juenger. That decline means viewing of major ad-supported kids’ networks like the Cartoon Network and Walt Disney Co.’s Disney XD has fallen by 63 per cent over the past seven years, Juenger said in a research note Thursday. At the same time, advertising has only fallen by 6.6 per cent over that time period and carriage fees have...