The two things I remember were Bucky the Commandos doing farm work (bailing hay?) and Bucky keeping pace with Steve mostly unnoticed, and the fact that Bucky was hungry all. the. time. but didn't say anything. (There may have been a mention of Steve getting larger rations, but I can't remember.)
I could be mixing up fics, but I don't think I am.
Please help, not being able to find it is driving me up a wall.
ETA: I'm pretty sure I read it on AO3.