Correction:

The Jena 6 march {also called "rally"} was held on September 20, 2007.

**

Another sign that I noted in photos about the Jena, Louisiana march was "Equality".

**

See this excerpt from a September 21, 2007 Wshington Post article which mentions two other slogans that were used in this march:

"The buses began arriving in Jena hours before dawn, the travelers stepping out stiff, yawning and bleary-eyed. Most wore black T-shirts with the message "Stop the criminalization of our children" and "What is the color of justice?"".*

http://www.washingtonpost.com/wp-dyn/content/article/2007/09/20/AR2007092000259.html?hpid=topnews


* [My italics]

-snip-

I'm not sure if marchers chanted those tee shirt slogans or the "equality" sign slogan.

I've read that putting slogans on tee shirts first happened in the early 1980s. Tee shirt/sweat shirt signage is an additional way of communicating one's position on issues that protestors in the 1960s, and 1970s didn't have.