Looking at someone else's question, I had this book come to mind all of a sudden. I read it somewhere in the 1998 to 2002 timeframe while I was in Dayton, OH (probably 1999-2000 because I vaguely remember that the snow storm the day I read it shut down my Intro to Religion class, which I took in that timeframe). It was a paperback book, probably from one of the main publishers like DAW or Baen. It showed a girl on a mount, I think a horse, with animals also riding with her. I believe she was in a dress, maybe riding side-saddle. There might have been a decrepit knight (old, armor badly fitting, drooping lance) on the cover as well.
What little I remember of the plot was that the girl's mother died. A piece of black or brown bread was placed on her chest as she died and the daughter ate the piece of bread to consume her mother's sins to ensure she'd go to heaven (pretty standard "sin eater" plot point as per the Medieval practice) with the idea that she had her life ahead of her to atone for those sins. For some reason, she leaves the village immediately afterwards, accompanied with a bunch of animals that she could communicate with. The only one I recall distinctly (and she might have picked it up during her travel) was a turtle or tortoise (probably the latter). I mainly remember that because somewhere near the end of book, she's obtained her goal (which I don't remember what it was) and the tortoise has found a mate, and there's a description of the loud clacking that ensued as the tortoises mated and their shells collided.
I think maybe the half-remembered knight was a plot point, someone she met on her travels and accompanied her. Maybe he wound up as her romance? That part is a lot vaguer in my head.