Any idea when BBQ first appeared around Chicago?

While I have always associated BBQ with Chicago, I haven't been able to find any reference about when BBQ first appeared in Chicago. My wife once worked for an elderly gentleman who said he would fill his wagon w. ribs during the Depression. And one of my MIL's few excellent meals were ribs she learned to cook in the early 50's. There must be a tradition, but I have found very little about BBQ as a business.

Can anyone point to some info, or have some recollection?

http://chicago.eater.com/archives/2011/ ... go-bbq.php

Makes sense that it would follow the Great Migration.