Two versions in Cox, Folk-Songs of the South, No. 6, have the verse: 'What shall we do for meat to ate', and go on to the verses with the dead horse and the eyes as the repast. These were collected c. 1916 in West Virginia; the similar verses in Randolph (coll. 1930s) are from Missouri.

William A. Owens collected the song from both Whites ad Negroes in Texas, and said a version he found in the Carolinas had been learned in the 1880s. These Texas versions also included the three verses mentioned above, in variant forms. Tunes heard in Texas approximated "When Johnny Comes Marching Home."
Wm. A. Owens, Texas Folk Songs, 1950 (1976 ed.), "Three Black Crows," pp. 14-15 with music.

I am sure that this 'three crow' variation has been found in other areas as well.