I agree with this. But I do see what appears in this pic to be thickening of the tendons on the left rear below the hock and around swelling around the fetlock. The tail is in the way of the right hind but it would be interesting to compare the two.
I don’t think it can be determined from this angle if he actually has dropped fetlocks but I would be taking a very close look at his legs if it was my horse. Especially the hinds.