The second oldest African American cookbook is Fisher’s What Mrs. Fisher Knows About Old Southern Cooking, Soups, Pickles, Etc. She does not mention picnics in her text,  but fried chicken is a picnic staple.

Fried Chicken: Cut the chicken up, separating every joint, and wash it clean. Salt and pepper it, and roll into flour well. Have your fat very hot, and drop the pieces into it, and let cook brown. The chicken is done when the fork passes easily into it. After the chicken is all cooked, leave a little of the hot fat in the skillet; then take a tablespoon full of dry flour and brown it in the fat stirring it around, then pour water in and stir till the gravy is as thin as soup.  

See Abby Fisher. What Mrs. Fisher Knows About Old Southern Cooking, Soups, Pickles, Etc. San Francisco: Women’s Cooperative Printing Office, 1881; http://digital.lib.msu.edu/projects/cookbooks/html/authors/author_fisher.html