And here are two "cotton loading songs" from the John Lomax Collection at American Memory. The "Wake Up, Sleepy" seems to be more of an actual work song. I don't think either of them are being sung in an actual work situation with a work gang.

http://memory.loc.gov/cgi-bin/query/D?lomaxbib:84:./temp/~ammem_ua2p::

http://memory.loc.gov/cgi-bin/query/D?lomaxbib:73:./temp/~ammem_ua2p::