Yes it is silver streaks, rather then bleaching.She is still bay. Is the tail getting silver streaks through it? If so this may well be a gulastra plume. My dartmoor's didn't start showing through until he was 6/7yo. If not she could just be burning/staining it peeing on it.
?Lol, my friend commented the other day, while running her hands through my pony’s tail “aww, she has silver streaks in her tail”
Me: “err, that’s pee”
?