Looking at this, I would say that it is just a hill dressing that has taken place (for the Southerner's I shall explain) it is pretty common practice when shooting cull beasts as you know to bag a few from one bunch, then what happens is that all the beasts are dragged or driven to a central location where they can be dressed out for transportation back to the larder. A hill dressing usually consists of whipping off the legs off from the knuckle then as it is probably not a good head (the first pic) or a hind or going to the kennels would be discarded. It looks from the pictures that the actual gralloch isn't present which usually ties in, as they would be gralloched in one location i.e. where they drop then dressed together possibly when they are all aboard the Argo. It isn't pretty but if you have a wheen of beasts to take home and light is failing this is a good way for your ghillie to get a start made when the stalker is trying to bag another couple.
I am not saying that this is best practice and not leaving it by a watercourse would be a start but it looks like a fairly stagnant burn to me. But personally I would expect to see this really through the harder winter months when things are getting properly tight for time when hind shooting.
Clum.....