"Eastern front" may require some definition. J. 25 & 38 flew in Macedonia but my impression is that no dedicated jastas were assigned to Russia.
The Jasta Pilots may have dealt with that subject but it's unavailable to me just now. More likely, the Ostfront fliegerabteilungen operated as they did in the west early in the war: mixed recon and bombing units with some fighter types attached. Probably a real logistics/maintenance headache but adequate to the threat posed by the opposition.