I was trying to avoid being long-winded when I wrote before. I was reacting to comments that "fallow doe" was metaphor for "pregnant woman" and I think that is impossible. However, we know the doe is pregnant because the ballad says so explicitly. I also thought looking into medieval hunting lore about fallow deer might be useful, but I just spent some time doing that and can't find anything pertinent.

I think the narrator's (a raven?) viewpoint is interesting. Things are described but not understood, like a small child might describe something like a wedding. I imagine the ballad as sung at the end of a tale about a knight and a deer-woman (human part of the time, a doe otherwise). He is killed for some reason and his body left for the ravens. The ballad sums up how he is buried and the woman dies (in childbirth?).