Literally ten minutes ago, I learnt about DSLD disease and began researching it.
I have heard a number of things, such as that it IS found in thoroughbreds. Diddly is 3/4 thoroughbred, and 1/4 Irish Draught.
I've also heard that they shift their feet from side to side, to ease the pain. Diddly will often lift one leg, then the other (just the front) almost like he's weaving, but he isn't. I don't think he does it because he is in pain, because I watch him when he's doing it, and he doesn't show any signs.
Diddly has slightly weak pasterns (I wouldn't call them low, but none the less) on his back legs. I'm terrified that they will drop.
Lastly, he will occasionally lift his left hind leg up then put it back down. I have a feeling that it's when he's sort of threatening to kick me. Just a warning, as he usually does it if I walk near his hind end when he''s feeding. I never did think anything of it until ten minutes ago.
I am literally TERRIFIED, because nobodies ever told me about this disease, nor have the majority of my horsey friends or family ever heard of it, yet from what I've heard its pretty common.