Evans may have taken the photo from an electric post like this one.
“Possible now to color yolks of eggs “red, white and blue” by feeding hens different feeds,” April 7, 1939, by Harris & Ewing, via Library of Congress Prints and Photographs Division.
Washington, D.C., April 7. . . . Charles A. Denton, Junior Chemist, poultry nutrition laboratory of the National Agriculture Research Center, Beltsville, Maryland, feeding a hen a certain food to produce a definite colored yolk.
— from the original Harris & Ewing caption
Blue eggs and ham?
. . . Yesterday the egg so fresh
it felt hot in his hand and he pressed it
to his ear. . . .
riveted to the secret of birds
caught up inside his fist. . . .
— Naomi Shihab Nye, from “Boy and Egg“
Mangum was a traveling photographer who worked along a rail circuit in North Carolina, Virginia, and West Virginia. You can see his portraits here.
A fenced-in backyard in Georgia, ca. 1899, via Library of Congress Prints and Photographs Division.
These photos were included in one of several albums depicting African American life, which were compiled by W. E. B. Du Bois for the 1900 Paris Exposition.
There’s a brief history of the American backyard here. Until the 20th century, it was a space for work, not recreation.